Module:String: Difference between revisions
m 1 revision imported |
en>Lectonar m Changed protection level for "Module:String": request at RfP ([Edit=Require template editor access] (indefinite) [Move=Require template editor access] (indefinite)) |
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--[[ | |||
This module is intended to provide access to basic string functions. | |||
Most of the functions provided here can be invoked with named parameters, | |||
unnamed parameters, or a mixture. If named parameters are used, Mediawiki will | |||
automatically remove any leading or trailing whitespace from the parameter. | |||
Depending on the intended use, it may be advantageous to either preserve or | |||
remove such whitespace. | |||
Global options | |||
ignore_errors: If set to 'true' or 1, any error condition will result in | |||
an empty string being returned rather than an error message. | |||
error_category: If an error occurs, specifies the name of a category to | |||
include with the error message. The default category is | |||
[Category:Errors reported by Module String]. | |||
no_category: If set to 'true' or 1, no category will be added if an error | |||
is generated. | |||
Unit tests for this module are available at Module:String/tests. | |||
]] | |||
local str = {} | |||
--[[ | --[[ | ||
Line 27: | Line 31: | ||
Usage: | Usage: | ||
{{#invoke: | {{#invoke:String|len|target_string|}} | ||
OR | OR | ||
{{#invoke: | {{#invoke:String|len|s=target_string}} | ||
Parameters | Parameters | ||
Line 35: | Line 39: | ||
If invoked using named parameters, Mediawiki will automatically remove any leading or | If invoked using named parameters, Mediawiki will automatically remove any leading or | ||
trailing whitespace from the target string. | trailing whitespace from the target string. | ||
]] | ]] | ||
function str.len(frame) | function str.len( frame ) | ||
local new_args = str._getParameters( frame.args, {'s'} ); | |||
local s = new_args['s'] or ''; | |||
return mw.ustring.len( s ) | |||
end | end | ||
Line 49: | Line 53: | ||
Usage: | Usage: | ||
{{#invoke: | {{#invoke:String|sub|target_string|start_index|end_index}} | ||
OR | OR | ||
{{#invoke: | {{#invoke:String|sub|s=target_string|i=start_index|j=end_index}} | ||
Parameters | Parameters | ||
Line 59: | Line 63: | ||
The first character of the string is assigned an index of 1. If either i or j | The first character of the string is assigned an index of 1. If either i or j | ||
is a negative value, it is interpreted the same as selecting a character by | is a negative value, it is interpreted the same as selecting a character by | ||
counting from the end of the string. Hence, a value of -1 is the same as | counting from the end of the string. Hence, a value of -1 is the same as | ||
selecting the last character of the string. | selecting the last character of the string. | ||
If the requested indices are out of range for the given string, an error is | If the requested indices are out of range for the given string, an error is | ||
reported. | reported. | ||
]] | ]] | ||
function str.sub(frame) | function str.sub( frame ) | ||
local new_args = str._getParameters( frame.args, { 's', 'i', 'j' } ); | |||
local s = new_args['s'] or ''; | |||
local i = tonumber( new_args['i'] ) or 1; | |||
local j = tonumber( new_args['j'] ) or -1; | |||
local len = mw.ustring.len( s ); | |||
-- Convert negatives for range checking | |||
if i < 0 then | |||
i = len + i + 1; | |||
end | |||
if j < 0 then | |||
j = len + j + 1; | |||
end | |||
if i > len or j > len or i < 1 or j < 1 then | |||
return str._error( 'String subset index out of range' ); | |||
end | |||
if j < i then | |||
return str._error( 'String subset indices out of order' ); | |||
end | |||
return mw.ustring.sub( s, i, j ) | |||
end | end | ||
Line 96: | Line 100: | ||
to maintain these older templates. | to maintain these older templates. | ||
]] | ]] | ||
function str.sublength(frame) | function str.sublength( frame ) | ||
local i = tonumber( frame.args.i ) or 0 | |||
local len = tonumber( frame.args.len ) | |||
return mw.ustring.sub( frame.args.s, i + 1, len and ( i + len ) ) | |||
end | end | ||
Line 105: | Line 109: | ||
match | match | ||
This function returns a substring from the source string that matches a | This function returns a substring from the source string that matches a | ||
specified pattern. | specified pattern. | ||
Usage: | Usage: | ||
{{#invoke: | {{#invoke:String|match|source_string|pattern_string|start_index|match_number|plain_flag|nomatch_output}} | ||
OR | OR | ||
{{#invoke: | {{#invoke:String|pos|s=source_string|pattern=pattern_string|start=start_index | ||
|match=match_number|plain=plain_flag|nomatch=nomatch_output}} | |match=match_number|plain=plain_flag|nomatch=nomatch_output}} | ||
Line 119: | Line 123: | ||
start: The index within the source string to start the search. The first | start: The index within the source string to start the search. The first | ||
character of the string has index 1. Defaults to 1. | character of the string has index 1. Defaults to 1. | ||
match: In some cases it may be possible to make multiple matches on a single | match: In some cases it may be possible to make multiple matches on a single | ||
string. This specifies which match to return, where the first match is | string. This specifies which match to return, where the first match is | ||
match= 1. If a negative number is specified then a match is returned | match= 1. If a negative number is specified then a match is returned | ||
counting from the last match. Hence match = -1 is the same as requesting | counting from the last match. Hence match = -1 is the same as requesting | ||
the last match. Defaults to 1. | the last match. Defaults to 1. | ||
Line 129: | Line 133: | ||
If invoked using named parameters, Mediawiki will automatically remove any leading or | If invoked using named parameters, Mediawiki will automatically remove any leading or | ||
trailing whitespace from each string. In some circumstances this is desirable, in | trailing whitespace from each string. In some circumstances this is desirable, in | ||
other cases one may want to preserve the whitespace. | other cases one may want to preserve the whitespace. | ||
If the match_number or start_index are out of range for the string being queried, then | If the match_number or start_index are out of range for the string being queried, then | ||
this function generates an error. An error is also generated if no match is found. | this function generates an error. An error is also generated if no match is found. | ||
If one adds the parameter ignore_errors=true, then the error will be suppressed and | If one adds the parameter ignore_errors=true, then the error will be suppressed and | ||
an empty string will be returned on any failure. | an empty string will be returned on any failure. | ||
Line 144: | Line 148: | ||
]] | ]] | ||
function str.match(frame) | function str.match( frame ) | ||
local new_args = str._getParameters( frame.args, {'s', 'pattern', 'start', 'match', 'plain', 'nomatch'} ); | |||
local s = new_args['s'] or ''; | |||
local start = tonumber( new_args['start'] ) or 1; | |||
local plain_flag = str._getBoolean( new_args['plain'] or false ); | |||
local pattern = new_args['pattern'] or ''; | |||
local match_index = math.floor( tonumber(new_args['match']) or 1 ); | |||
local nomatch = new_args['nomatch']; | |||
if s == '' then | |||
return str._error( 'Target string is empty' ); | |||
end | |||
if pattern == '' then | |||
return str._error( 'Pattern string is empty' ); | |||
end | |||
if math.abs(start) < 1 or math.abs(start) > mw.ustring.len( s ) then | |||
return str._error( 'Requested start is out of range' ); | |||
end | |||
if match_index == 0 then | |||
return str._error( 'Match index is out of range' ); | |||
end | |||
if plain_flag then | |||
pattern = str._escapePattern( pattern ); | |||
end | |||
local result | |||
if match_index == 1 then | |||
-- Find first match is simple case | |||
result = mw.ustring.match( s, pattern, start ) | |||
else | |||
if start > 1 then | |||
s = mw.ustring.sub( s, start ); | |||
end | |||
local iterator = mw.ustring.gmatch(s, pattern); | |||
if match_index > 0 then | |||
-- Forward search | |||
for w in iterator do | |||
match_index = match_index - 1; | |||
if match_index == 0 then | |||
result = w; | |||
break; | |||
end | |||
end | |||
else | |||
-- Reverse search | |||
local result_table = {}; | |||
local count = 1; | |||
for w in iterator do | |||
result_table[count] = w; | |||
count = count + 1; | |||
end | |||
result = result_table[ count + match_index ]; | |||
end | |||
end | |||
if result == nil then | |||
if nomatch == nil then | |||
return str._error( 'Match not found' ); | |||
else | |||
return nomatch; | |||
end | |||
else | |||
return result; | |||
end | |||
end | end | ||
Line 218: | Line 222: | ||
Usage: | Usage: | ||
{{#invoke: | {{#invoke:String|pos|target_string|index_value}} | ||
OR | OR | ||
{{#invoke: | {{#invoke:String|pos|target=target_string|pos=index_value}} | ||
Parameters | Parameters | ||
Line 227: | Line 231: | ||
If invoked using named parameters, Mediawiki will automatically remove any leading or | If invoked using named parameters, Mediawiki will automatically remove any leading or | ||
trailing whitespace from the target string. In some circumstances this is desirable, in | trailing whitespace from the target string. In some circumstances this is desirable, in | ||
other cases one may want to preserve the whitespace. | other cases one may want to preserve the whitespace. | ||
The first character has an index value of 1. | The first character has an index value of 1. | ||
If one requests a negative value, this function will select a character by counting backwards | If one requests a negative value, this function will select a character by counting backwards | ||
from the end of the string. In other words pos = -1 is the same as asking for the last character. | from the end of the string. In other words pos = -1 is the same as asking for the last character. | ||
A requested value of zero, or a value greater than the length of the string returns an error. | A requested value of zero, or a value greater than the length of the string returns an error. | ||
]] | ]] | ||
function str.pos(frame) | function str.pos( frame ) | ||
local new_args = str._getParameters( frame.args, {'target', 'pos'} ); | |||
local target_str = new_args['target'] or ''; | |||
local pos = tonumber( new_args['pos'] ) or 0; | |||
if pos == 0 or math.abs(pos) > mw.ustring.len( target_str ) then | |||
return str._error( 'String index out of range' ); | |||
end | |||
return mw.ustring.sub( target_str, pos, pos ); | |||
end | end | ||
Line 253: | Line 257: | ||
This function duplicates the behavior of {{str_find}}, including all of its quirks. | This function duplicates the behavior of {{str_find}}, including all of its quirks. | ||
This is provided in order to support existing templates, but is NOT RECOMMENDED for | This is provided in order to support existing templates, but is NOT RECOMMENDED for | ||
new code and templates. New code is recommended to use the "find" function instead. | new code and templates. New code is recommended to use the "find" function instead. | ||
Line 263: | Line 267: | ||
separatetly. | separatetly. | ||
]] | ]] | ||
function str.str_find(frame) | function str.str_find( frame ) | ||
local new_args = str._getParameters( frame.args, {'source', 'target'} ); | |||
local source_str = new_args['source'] or ''; | |||
local target_str = new_args['target'] or ''; | |||
if target_str == '' then | |||
return 1; | |||
end | |||
local start = mw.ustring.find( source_str, target_str, 1, true ) | |||
if start == nil then | |||
start = -1 | |||
end | |||
return start | |||
end | end | ||
Line 287: | Line 291: | ||
Usage: | Usage: | ||
{{#invoke: | {{#invoke:String|find|source_str|target_string|start_index|plain_flag}} | ||
OR | OR | ||
{{#invoke: | {{#invoke:String|find|source=source_str|target=target_str|start=start_index|plain=plain_flag}} | ||
Parameters | Parameters | ||
Line 299: | Line 303: | ||
If invoked using named parameters, Mediawiki will automatically remove any leading or | If invoked using named parameters, Mediawiki will automatically remove any leading or | ||
trailing whitespace from the parameter. In some circumstances this is desirable, in | trailing whitespace from the parameter. In some circumstances this is desirable, in | ||
other cases one may want to preserve the whitespace. | other cases one may want to preserve the whitespace. | ||
This function returns the first index >= "start" where "target" can be found | This function returns the first index >= "start" where "target" can be found | ||
within "source". Indices are 1-based. If "target" is not found, then this | within "source". Indices are 1-based. If "target" is not found, then this | ||
function returns | function returns 0. If either "source" or "target" are missing / empty, this | ||
function also returns | function also returns 0. | ||
This function should be safe for UTF-8 strings. | This function should be safe for UTF-8 strings. | ||
]] | ]] | ||
function str.find(frame) | function str.find( frame ) | ||
local new_args = str._getParameters( frame.args, {'source', 'target', 'start', 'plain' } ); | |||
local source_str = new_args['source'] or ''; | |||
local pattern = new_args['target'] or ''; | |||
local start_pos = tonumber(new_args['start']) or 1; | |||
local plain = new_args['plain'] or true; | |||
if source_str == '' or pattern == '' then | |||
return 0; | |||
end | |||
plain = str._getBoolean( plain ); | |||
local start = mw.ustring.find( source_str, pattern, start_pos, plain ) | |||
if start == nil then | |||
start = 0 | |||
end | |||
return start | |||
end | end | ||
Line 329: | Line 341: | ||
Usage: | Usage: | ||
{{#invoke: | {{#invoke:String|replace|source_str|pattern_string|replace_string|replacement_count|plain_flag}} | ||
OR | OR | ||
{{#invoke: | {{#invoke:String|replace|source=source_string|pattern=pattern_string|replace=replace_string| | ||
count=replacement_count|plain=plain_flag}} | count=replacement_count|plain=plain_flag}} | ||
Line 340: | Line 352: | ||
count: The number of occurences to replace, defaults to all. | count: The number of occurences to replace, defaults to all. | ||
plain: Boolean flag indicating that pattern should be understood as plain | plain: Boolean flag indicating that pattern should be understood as plain | ||
text and not as a Lua style regular expression, defaults to true | text and not as a Lua style regular expression, defaults to true | ||
]] | ]] | ||
function str.replace(frame) | function str.replace( frame ) | ||
local new_args = str._getParameters( frame.args, {'source', 'pattern', 'replace', 'count', 'plain' } ); | |||
local source_str = new_args['source'] or ''; | |||
local pattern = new_args['pattern'] or ''; | |||
local replace = new_args['replace'] or ''; | |||
local count = tonumber( new_args['count'] ); | |||
local plain = new_args['plain'] or true; | |||
if source_str == '' or pattern == '' then | |||
return source_str; | |||
end | |||
plain = str._getBoolean( plain ); | |||
if plain then | |||
pattern = str._escapePattern( pattern ); | |||
replace = mw.ustring.gsub( replace, "%%", "%%%%" ); --Only need to escape replacement sequences. | |||
end | |||
local result; | |||
if count ~= nil then | |||
result = mw.ustring.gsub( source_str, pattern, replace, count ); | |||
else | |||
result = mw.ustring.gsub( source_str, pattern, replace ); | |||
end | |||
return result; | |||
end | end | ||
--[[ | |||
--[[ | |||
simple function to pipe string.rep to templates. | simple function to pipe string.rep to templates. | ||
]] | ]] | ||
function str.rep(frame) | function str.rep( frame ) | ||
local repetitions = tonumber( frame.args[2] ) | |||
if not repetitions then | |||
return str._error( 'function rep expects a number as second parameter, received "' .. ( frame.args[2] or '' ) .. '"' ) | |||
end | |||
return string.rep( frame.args[1] or '', repetitions ) | |||
end | end | ||
--[[ | --[[ | ||
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we sometimes want to either preserve or remove that whitespace depending on the application. | we sometimes want to either preserve or remove that whitespace depending on the application. | ||
]] | ]] | ||
function str._getParameters(frame_args, arg_list) | function str._getParameters( frame_args, arg_list ) | ||
local new_args = {}; | |||
local index = 1; | |||
local value; | |||
for i,arg in ipairs( arg_list ) do | |||
value = frame_args[arg] | |||
if value == nil then | |||
value = frame_args[index]; | |||
index = index + 1; | |||
end | |||
new_args[arg] = value; | |||
end | |||
return new_args; | |||
end | end | ||
--[[ | --[[ | ||
Helper function to handle error messages. | Helper function to handle error messages. | ||
]] | ]] | ||
function str._error(error_str) | function str._error( error_str ) | ||
local frame = mw.getCurrentFrame(); | |||
local error_category = frame.args.error_category or 'Errors reported by Module String'; | |||
local ignore_errors = frame.args.ignore_errors or false; | |||
local no_category = frame.args.no_category or false; | |||
if str._getBoolean(ignore_errors) then | |||
return ''; | |||
end | |||
local error_str = '<strong class="error">String Module Error: ' .. error_str .. '</strong>'; | |||
if error_category ~= '' and not str._getBoolean( no_category ) then | |||
error_str = '[[Category:' .. error_category .. ']]' .. error_str; | |||
end | |||
return error_str; | |||
end | end | ||
Line 452: | Line 442: | ||
Helper Function to interpret boolean strings | Helper Function to interpret boolean strings | ||
]] | ]] | ||
function str._getBoolean(boolean_str) | function str._getBoolean( boolean_str ) | ||
local boolean_value; | |||
if type( boolean_str ) == 'string' then | |||
boolean_str = boolean_str:lower(); | |||
if boolean_str == 'false' or boolean_str == 'no' or boolean_str == '0' | |||
or boolean_str == '' then | |||
boolean_value = false; | |||
else | |||
boolean_value = true; | |||
end | |||
elseif type( boolean_str ) == 'boolean' then | |||
boolean_value = boolean_str; | |||
else | |||
error( 'No boolean value found' ); | |||
end | |||
return boolean_value | |||
end | end | ||
--[[ | --[[ | ||
Helper function that escapes all pattern characters | Helper function that escapes all pattern characters so that they will be treated | ||
as plain text. | as plain text. | ||
]] | ]] | ||
function str. | function str._escapePattern( pattern_str ) | ||
return mw.ustring.gsub( pattern_str, "([%(%)%.%%%+%-%*%?%[%^%$%]])", "%%%1" ); | |||
end | end | ||
return str | return str |
Revision as of 14:04, 4 March 2019
This Lua module is used in system messages, and on approximately 10,900,000 pages, or roughly 91382% of all pages. Changes to it can cause immediate changes to the Wikipedia user interface. To avoid major disruption and server load, any changes should be tested in the module's /sandbox or /testcases subpages, or in your own module sandbox. The tested changes can be added to this page in a single edit. Please discuss changes on the talk page before implementing them. |
This module is subject to page protection. It is a highly visible module in use by a very large number of pages, or is substituted very frequently. Because vandalism or mistakes would affect many pages, and even trivial editing might cause substantial load on the servers, it is protected from editing. |
Module:String (edit | talk | history | links | watch | logs)
This module is intended to provide access to basic string functions.
Most of the functions provided here can be invoked with named parameters, unnamed parameters, or a mixture. If named parameters are used, Mediawiki will automatically remove any leading or trailing whitespace from the parameter. Depending on the intended use, it may be advantageous to either preserve or remove such whitespace.
Global options
- ignore_errors
- If set to 'true' or 1, any error condition will result in an empty string being returned rather than an error message.
- error_category
- If an error occurs, specifies the name of a category to include with the error message. The default category is Category:Errors reported by Module String (0).
- no_category
- If set to 'true' or 1, no category will be added if an error is generated.
Unit tests for this module are available at Module:String/testcases.
len
This function returns the length of the target string.
Usage:
{{#invoke:String|len|target_string}}
OR
{{#invoke:String|len|s= target_string }}
Parameters:
- s
- The string whose length to report
Examples:
{{#invoke:String|len| abcdefghi }}
→ 11{{#invoke:String|len|s= abcdefghi }}
→ 9
sub
This function returns a substring of the target string at specified inclusive, one-indexed indices.
Usage:
{{#invoke:String|sub|target_string|start_index|end_index}}
OR
{{#invoke:String|sub|s= target_string |i= start_index |j= end_index }}
Parameters:
- s
- The string to return a subset of
- i
- The first index of the substring to return, defaults to 1.
- j
- The last index of the string to return, defaults to the last character.
The first character of the string is assigned an index of 1. If either i or j is a negative value, it is interpreted the same as selecting a character by counting from the end of the string. Hence, a value of -1 is the same as selecting the last character of the string.
If the requested indices are out of range for the given string, an error is reported. To avoid error messages, use {{#invoke:ustring|sub}} instead.
Examples:
"{{#invoke:String|sub| abcdefghi }}"
→ " abcdefghi ""{{#invoke:String|sub|s= abcdefghi }}"
→ "abcdefghi""{{#invoke:String|sub| abcdefghi | 3 }}"
→ "bcdefghi ""{{#invoke:String|sub|s= abcdefghi |i= 3 }}"
→ "cdefghi""{{#invoke:String|sub| abcdefghi | 3 | 4 }}"
→ "bc""{{#invoke:String|sub|s= abcdefghi |i= 3 |j= 4 }}"
→ "cd"
sublength
This function implements the features of {{str sub old}} and is kept in order to maintain these older templates. It returns a substring of the target string starting at a specified index and of a specified length.
Usage:
{{#invoke:String|sublength|s= target_string |i= start_index |len= length }}
Parameters:
- s
- The string
- i
- The starting index of the substring to return. The first character of the string is assigned an index of 0.
- len
- The length of the string to return, defaults to the last character.
Examples:
{{#invoke:String|sublength|s= abcdefghi }}
→ abcdefghi{{#invoke:String|sublength|s= abcdefghi |i= 3 }}
→ defghi{{#invoke:String|sublength|s= abcdefghi |i= 3 |len= 4 }}
→ defg
match
This function returns a substring from the source string that matches a specified pattern.
Usage:
{{#invoke:String|match|source_string|pattern_string|start_index|match_number|plain_flag|nomatch_output}}
OR
{{#invoke:String|match|s= source_string |pattern= pattern_string |start= start_index |match= match_number |plain= plain_flag |nomatch= nomatch_output }}
Parameters:
- s
- The string to search
- pattern
- The pattern or string to find within the string
- start
- The index within the source string to start the search. The first character of the string has index 1. Defaults to 1.
- match
- In some cases it may be possible to make multiple matches on a single string. This specifies which match to return, where the first match is match= 1. If a negative number is specified then a match is returned counting from the last match. Hence match = -1 is the same as requesting the last match. Defaults to 1.
- plain
- Boolean flag indicating that pattern should be understood as plain text and not as a Scribunto ustring pattern (a unicode-friendly Lua-style regular expression). Defaults to false (to change:
plain=true
) - nomatch
- If no match is found, output the "nomatch" value rather than an error.
- ignore_errors
- If no match is found and ignore_errors=true, output an empty string rather than an error.
If the match_number or start_index are out of range for the string being queried, then this function generates an error. An error is also generated if no match is found. If one adds the parameter ignore_errors=true, then the error will be suppressed and an empty string will be returned on any failure.
For information on constructing Lua patterns, a form of regular expression, see:
Examples:
{{#invoke:String|match| abc123def456 |%d+}}
→ 123{{#invoke:String|match|s= abc123def456 |pattern= %d+ }}
→ 123{{#invoke:String|match| abc123def456 |%d+|6}}
→ 23{{#invoke:String|match|s= abc123def456 |pattern= %d+ |start= 6 }}
→ 3{{#invoke:String|match|s= abc123def456 |pattern= %d+ |start= 6 |match= 2 }}
→ 456{{#invoke:String|match|s= abc123%d+ |pattern= %d+ }}
→ 123{{#invoke:String|match|s= abc123%d+ |pattern= %d+ |plain= true }}
→ %d+{{#invoke:String|match|s= abc |pattern= %d }}
→ String Module Error: Match not found{{#invoke:String|match|s= abc |pattern= %d |nomatch= No numeric characters in string }}
→ No numeric characters in string{{#invoke:String|match|s= abc |pattern= %d |ignore_errors= true }}
→{{#invoke:String|match|s= 0012001200 |pattern= 0*(%d*) }}
→ 12001200
pos
This function returns a single character from the target string at position pos.
Usage:
{{#invoke:String|pos|target_string|index_value}}
OR
{{#invoke:String|pos|target= target_string |pos= index_value }}
Parameters:
- target
- The string to search
- pos
- The index for the character to return
The first character has an index value of 1.
If one requests a negative value, this function will select a character by counting backwards from the end of the string. In other words pos = -1 is the same as asking for the last character.
A requested value of zero, or a value greater than the length of the string returns an error.
Examples:
{{#invoke:String|pos| abcdefghi | 4 }}
→ c{{#invoke:String|pos|target= abcdefghi |pos= 4 }}
→ d
str_find
This function duplicates the behavior of {{str_find}}, including all of its quirks. This is provided in order to support existing templates, but is NOT RECOMMENDED for new code and templates. New code is recommended to use the "find" function instead.
Returns the first index in "source" that is a match to "target". Indexing is 1-based, and the function returns -1 if the "target" string is not present in "source".
Important Note: If the "target" string is empty / missing, this function returns a value of "1", which is generally unexpected behavior, and must be accounted for separately.
Usage:
{{#invoke:String|str_find|source_string|target_string}}
OR
{{#invoke:String|str_find|source= source_string |target= target_string }}
Parameters:
- source
- The string to search
- target
- The string to find within source
Examples:
{{#invoke:String|str_find| abc123def }}
→ 1{{#invoke:String|str_find|source= abc123def }}
→ 1{{#invoke:String|str_find| abc123def |123}}
→ 5{{#invoke:String|str_find|source= abc123def |target= 123 }}
→ 4{{#invoke:String|str_find| abc123def |not}}
→ -1
find
This function allows one to search for a target string or pattern within another string.
Usage:
{{#invoke:String|find|source_string|target_string|start_index|plain_flag}}
OR
{{#invoke:String|find|source= source_string |target= target_string |start= start_index |plain= plain_flag }}
Parameters:
- source
- The string to search
- target
- The string or pattern to find within source
- start
- The index within the source string to start the search, defaults to 1
- plain
- Boolean flag indicating that target should be understood as plain text and not as a Scribunto ustring pattern (a unicode-friendly Lua-style regular expression); defaults to true
This function returns the first index >= "start" where "target" can be found within "source". Indices are 1-based. If "target" is not found, then this function returns 0. If either "source" or "target" are missing / empty, this function also returns 0.
This function should be safe for UTF-8 strings.
Examples:
{{#invoke:String|find|abc123def|12}}
→ 4
{{#invoke:String|find|source=abc123def|target=12}}
→ 4
{{#invoke:String|find|source=abc123def|target=pqr}}
→ 0
{{#invoke:String|find| abc123def |123}}
→ 5{{#invoke:String|find|source= abc123def |target= 123 }}
→ 4{{#invoke:String|find|source=abc123def|target=%d |start=3 |plain=false }}
→ 4
When using unnamed parameters, preceding and trailing spaces are kept and counted:
{{#invoke:String|find| abc123def |c|false}}
→ 5{{#invoke:String|find|source= abc123def |target=c|plain=false}}
→ 3{{#invoke:string|find|abc 123 def|%s|plain=false}}
→ 4
Testing for the presence of a string:
{{#ifexpr:{{#invoke:string|find|haystack|needle}}|Found needle|Didn't find needle}}
→ Didn't find needle
replace (gsub)
This function allows one to replace a target string or pattern within another string. To Lua programmers: this function works internally by calling string.gsub
.
Usage:
{{#invoke:String|replace|source_str|pattern_string|replace_string|replacement_count|plain_flag}}
OR
{{#invoke:String|replace|source= source_string |pattern= pattern_string |replace= replace_string |count= replacement_count |plain= plain_flag }}
Parameters:
- source
- The string to search
- pattern
- The string or pattern to find within source
- replace
- The replacement text
- count
- The number of occurrences to replace; defaults to all
- plain
- Boolean flag indicating that pattern should be understood as plain text and not as a Scribunto ustring pattern (a unicode-friendly Lua-style regular expression); defaults to true
Examples:
"{{#invoke:String|replace| abc123def456 |123|XYZ}}"
→ " abcXYZdef456 ""{{#invoke:String|replace|source= abc123def456 |pattern= 123 |replace= XYZ }}"
→ "abcXYZdef456""{{#invoke:String|replace| abc123def456 |%d+|XYZ|1|false}}"
→ " abcXYZdef456 ""{{#invoke:String|replace|source= abc123def456 |pattern= %d+ |replace= XYZ |count=1 |plain= false }}"
→ "abcXYZdef456""{{#invoke:String|replace|source= abc123def456 |pattern= %d+ |replace= XYZ |plain= false }}"
→ "abcXYZdefXYZ"{{#invoke:String|replace|source= 0012001200 |pattern= ^0* |plain= false }}
→ 12001200
rep
Repeats a string n times. A simple function to pipe string.rep to templates.
Usage:
{{#invoke:String|rep|source|count}}
Parameters:
- source
- The string to repeat
- count
- The number of repetitions.
Examples:
"{{#invoke:String|rep|hello|3}}"
→ "hellohellohello""{{#invoke:String|rep| hello | 3 }}"
→ " hello hello hello "
escapePattern
In a Lua pattern, changes a class character into a literal character. For example: in a pattern, character .
catches "any character"; escapePattern will convert it to %.
, catching just the literal character ".".
Usage:
{{#invoke:String|escapePattern|pattern_string}}
Parameters:
- pattern_string
- The pattern string to escape
Examples:
"{{#invoke:String|escapePattern|A.D.}}"
→ "Script error: The function "escapePattern" does not exist.""{{#invoke:String|escapePattern|10%}}"
→ "Script error: The function "escapePattern" does not exist."
count
Counts the number of times a given pattern appears in the arguments that get passed on to this module. Counts disjoint matches only.
Usage:
{{#invoke:String|count|source_str|pattern_string|plain_flag}}
OR
{{#invoke:String|count|source= source_string |pattern= pattern_string|plain= plain_flag }}
Parameters:
- source_string
- The string to count occurrences in
- pattern
- The string or pattern to count occurrences of within source
- plain
- Boolean flag indicating that pattern should be understood as plain text and not as a Scribunto ustring pattern (a unicode-friendly Lua-style regular expression); defaults to true
Examples:
- Count of 'a':
"{{#invoke:String|count|aabbcc|a}}"
→ "Script error: The function "count" does not exist." - Count occurrences of 'aba':
"{{#invoke:String|count|ababababab|aba}}"
→ "Script error: The function "count" does not exist." - Count of "either 'a' or 'c' ":
"{{#invoke:String|count|aabbcc|[ac]|plain=false}}"
→ "Script error: The function "count" does not exist." - Count of "not 'a' ":
"{{#invoke:String|count|aaabaaac|[^a]|plain=false}}"
→ "Script error: The function "count" does not exist." - Count of "starts with 'a' ":
"{{#invoke:String|count|aaabaaac|^a|plain=false}}"
→ "Script error: The function "count" does not exist."
join
Joins all strings passed as arguments into one string, treating the first argument as a separator
Usage:
{{#invoke:String|join|separator|string1|string2|...}}
Parameters:
- separator
- String that separates each string being joined together
- Note that leading and trailing spaces are not stripped from the separator.
- string1/string2/...
- Strings being joined together
Examples:
"{{#invoke:String|join|x|foo|bar|baz}}"
→ "Script error: The function "join" does not exist.""{{#invoke:String|join||a|b|c|d|e|f|g}}"
→ "Script error: The function "join" does not exist.""{{#invoke:String|join|,|a|b|c|d|e|f|g}}"
→ "Script error: The function "join" does not exist.""{{#invoke:String|join|, |a|b|c|d|e|f|g}}"
→ "Script error: The function "join" does not exist.""{{#invoke:String|join| – |a|b|c|d|e|f|g}}"
→ "Script error: The function "join" does not exist."
The preceding example uses the html entity – but the unicode character also works.
endswith
Usage:
{{#invoke:String|endswith|source_str|search_string}}
OR
{{#invoke:String|endswith|source= source_string |pattern= search_string}}
Returns "yes" if the source string ends with the search string. Use named parameters to have the strings trimmed before use. Despite the parameter name, search_string is not a Lua pattern, it is interpreted literally.
"{{#invoke:String|endswith|xxxyyy|y}}"
→ "Script error: The function "endswith" does not exist.""{{#invoke:String|endswith|xxxyyy|z}}"
→ "Script error: The function "endswith" does not exist."
See also
--[[
This module is intended to provide access to basic string functions.
Most of the functions provided here can be invoked with named parameters,
unnamed parameters, or a mixture. If named parameters are used, Mediawiki will
automatically remove any leading or trailing whitespace from the parameter.
Depending on the intended use, it may be advantageous to either preserve or
remove such whitespace.
Global options
ignore_errors: If set to 'true' or 1, any error condition will result in
an empty string being returned rather than an error message.
error_category: If an error occurs, specifies the name of a category to
include with the error message. The default category is
[Category:Errors reported by Module String].
no_category: If set to 'true' or 1, no category will be added if an error
is generated.
Unit tests for this module are available at Module:String/tests.
]]
local str = {}
--[[
len
This function returns the length of the target string.
Usage:
{{#invoke:String|len|target_string|}}
OR
{{#invoke:String|len|s=target_string}}
Parameters
s: The string whose length to report
If invoked using named parameters, Mediawiki will automatically remove any leading or
trailing whitespace from the target string.
]]
function str.len( frame )
local new_args = str._getParameters( frame.args, {'s'} );
local s = new_args['s'] or '';
return mw.ustring.len( s )
end
--[[
sub
This function returns a substring of the target string at specified indices.
Usage:
{{#invoke:String|sub|target_string|start_index|end_index}}
OR
{{#invoke:String|sub|s=target_string|i=start_index|j=end_index}}
Parameters
s: The string to return a subset of
i: The fist index of the substring to return, defaults to 1.
j: The last index of the string to return, defaults to the last character.
The first character of the string is assigned an index of 1. If either i or j
is a negative value, it is interpreted the same as selecting a character by
counting from the end of the string. Hence, a value of -1 is the same as
selecting the last character of the string.
If the requested indices are out of range for the given string, an error is
reported.
]]
function str.sub( frame )
local new_args = str._getParameters( frame.args, { 's', 'i', 'j' } );
local s = new_args['s'] or '';
local i = tonumber( new_args['i'] ) or 1;
local j = tonumber( new_args['j'] ) or -1;
local len = mw.ustring.len( s );
-- Convert negatives for range checking
if i < 0 then
i = len + i + 1;
end
if j < 0 then
j = len + j + 1;
end
if i > len or j > len or i < 1 or j < 1 then
return str._error( 'String subset index out of range' );
end
if j < i then
return str._error( 'String subset indices out of order' );
end
return mw.ustring.sub( s, i, j )
end
--[[
This function implements that features of {{str sub old}} and is kept in order
to maintain these older templates.
]]
function str.sublength( frame )
local i = tonumber( frame.args.i ) or 0
local len = tonumber( frame.args.len )
return mw.ustring.sub( frame.args.s, i + 1, len and ( i + len ) )
end
--[[
match
This function returns a substring from the source string that matches a
specified pattern.
Usage:
{{#invoke:String|match|source_string|pattern_string|start_index|match_number|plain_flag|nomatch_output}}
OR
{{#invoke:String|pos|s=source_string|pattern=pattern_string|start=start_index
|match=match_number|plain=plain_flag|nomatch=nomatch_output}}
Parameters
s: The string to search
pattern: The pattern or string to find within the string
start: The index within the source string to start the search. The first
character of the string has index 1. Defaults to 1.
match: In some cases it may be possible to make multiple matches on a single
string. This specifies which match to return, where the first match is
match= 1. If a negative number is specified then a match is returned
counting from the last match. Hence match = -1 is the same as requesting
the last match. Defaults to 1.
plain: A flag indicating that the pattern should be understood as plain
text. Defaults to false.
nomatch: If no match is found, output the "nomatch" value rather than an error.
If invoked using named parameters, Mediawiki will automatically remove any leading or
trailing whitespace from each string. In some circumstances this is desirable, in
other cases one may want to preserve the whitespace.
If the match_number or start_index are out of range for the string being queried, then
this function generates an error. An error is also generated if no match is found.
If one adds the parameter ignore_errors=true, then the error will be suppressed and
an empty string will be returned on any failure.
For information on constructing Lua patterns, a form of [regular expression], see:
* http://www.lua.org/manual/5.1/manual.html#5.4.1
* http://www.mediawiki.org/wiki/Extension:Scribunto/Lua_reference_manual#Patterns
* http://www.mediawiki.org/wiki/Extension:Scribunto/Lua_reference_manual#Ustring_patterns
]]
function str.match( frame )
local new_args = str._getParameters( frame.args, {'s', 'pattern', 'start', 'match', 'plain', 'nomatch'} );
local s = new_args['s'] or '';
local start = tonumber( new_args['start'] ) or 1;
local plain_flag = str._getBoolean( new_args['plain'] or false );
local pattern = new_args['pattern'] or '';
local match_index = math.floor( tonumber(new_args['match']) or 1 );
local nomatch = new_args['nomatch'];
if s == '' then
return str._error( 'Target string is empty' );
end
if pattern == '' then
return str._error( 'Pattern string is empty' );
end
if math.abs(start) < 1 or math.abs(start) > mw.ustring.len( s ) then
return str._error( 'Requested start is out of range' );
end
if match_index == 0 then
return str._error( 'Match index is out of range' );
end
if plain_flag then
pattern = str._escapePattern( pattern );
end
local result
if match_index == 1 then
-- Find first match is simple case
result = mw.ustring.match( s, pattern, start )
else
if start > 1 then
s = mw.ustring.sub( s, start );
end
local iterator = mw.ustring.gmatch(s, pattern);
if match_index > 0 then
-- Forward search
for w in iterator do
match_index = match_index - 1;
if match_index == 0 then
result = w;
break;
end
end
else
-- Reverse search
local result_table = {};
local count = 1;
for w in iterator do
result_table[count] = w;
count = count + 1;
end
result = result_table[ count + match_index ];
end
end
if result == nil then
if nomatch == nil then
return str._error( 'Match not found' );
else
return nomatch;
end
else
return result;
end
end
--[[
pos
This function returns a single character from the target string at position pos.
Usage:
{{#invoke:String|pos|target_string|index_value}}
OR
{{#invoke:String|pos|target=target_string|pos=index_value}}
Parameters
target: The string to search
pos: The index for the character to return
If invoked using named parameters, Mediawiki will automatically remove any leading or
trailing whitespace from the target string. In some circumstances this is desirable, in
other cases one may want to preserve the whitespace.
The first character has an index value of 1.
If one requests a negative value, this function will select a character by counting backwards
from the end of the string. In other words pos = -1 is the same as asking for the last character.
A requested value of zero, or a value greater than the length of the string returns an error.
]]
function str.pos( frame )
local new_args = str._getParameters( frame.args, {'target', 'pos'} );
local target_str = new_args['target'] or '';
local pos = tonumber( new_args['pos'] ) or 0;
if pos == 0 or math.abs(pos) > mw.ustring.len( target_str ) then
return str._error( 'String index out of range' );
end
return mw.ustring.sub( target_str, pos, pos );
end
--[[
str_find
This function duplicates the behavior of {{str_find}}, including all of its quirks.
This is provided in order to support existing templates, but is NOT RECOMMENDED for
new code and templates. New code is recommended to use the "find" function instead.
Returns the first index in "source" that is a match to "target". Indexing is 1-based,
and the function returns -1 if the "target" string is not present in "source".
Important Note: If the "target" string is empty / missing, this function returns a
value of "1", which is generally unexpected behavior, and must be accounted for
separatetly.
]]
function str.str_find( frame )
local new_args = str._getParameters( frame.args, {'source', 'target'} );
local source_str = new_args['source'] or '';
local target_str = new_args['target'] or '';
if target_str == '' then
return 1;
end
local start = mw.ustring.find( source_str, target_str, 1, true )
if start == nil then
start = -1
end
return start
end
--[[
find
This function allows one to search for a target string or pattern within another
string.
Usage:
{{#invoke:String|find|source_str|target_string|start_index|plain_flag}}
OR
{{#invoke:String|find|source=source_str|target=target_str|start=start_index|plain=plain_flag}}
Parameters
source: The string to search
target: The string or pattern to find within source
start: The index within the source string to start the search, defaults to 1
plain: Boolean flag indicating that target should be understood as plain
text and not as a Lua style regular expression, defaults to true
If invoked using named parameters, Mediawiki will automatically remove any leading or
trailing whitespace from the parameter. In some circumstances this is desirable, in
other cases one may want to preserve the whitespace.
This function returns the first index >= "start" where "target" can be found
within "source". Indices are 1-based. If "target" is not found, then this
function returns 0. If either "source" or "target" are missing / empty, this
function also returns 0.
This function should be safe for UTF-8 strings.
]]
function str.find( frame )
local new_args = str._getParameters( frame.args, {'source', 'target', 'start', 'plain' } );
local source_str = new_args['source'] or '';
local pattern = new_args['target'] or '';
local start_pos = tonumber(new_args['start']) or 1;
local plain = new_args['plain'] or true;
if source_str == '' or pattern == '' then
return 0;
end
plain = str._getBoolean( plain );
local start = mw.ustring.find( source_str, pattern, start_pos, plain )
if start == nil then
start = 0
end
return start
end
--[[
replace
This function allows one to replace a target string or pattern within another
string.
Usage:
{{#invoke:String|replace|source_str|pattern_string|replace_string|replacement_count|plain_flag}}
OR
{{#invoke:String|replace|source=source_string|pattern=pattern_string|replace=replace_string|
count=replacement_count|plain=plain_flag}}
Parameters
source: The string to search
pattern: The string or pattern to find within source
replace: The replacement text
count: The number of occurences to replace, defaults to all.
plain: Boolean flag indicating that pattern should be understood as plain
text and not as a Lua style regular expression, defaults to true
]]
function str.replace( frame )
local new_args = str._getParameters( frame.args, {'source', 'pattern', 'replace', 'count', 'plain' } );
local source_str = new_args['source'] or '';
local pattern = new_args['pattern'] or '';
local replace = new_args['replace'] or '';
local count = tonumber( new_args['count'] );
local plain = new_args['plain'] or true;
if source_str == '' or pattern == '' then
return source_str;
end
plain = str._getBoolean( plain );
if plain then
pattern = str._escapePattern( pattern );
replace = mw.ustring.gsub( replace, "%%", "%%%%" ); --Only need to escape replacement sequences.
end
local result;
if count ~= nil then
result = mw.ustring.gsub( source_str, pattern, replace, count );
else
result = mw.ustring.gsub( source_str, pattern, replace );
end
return result;
end
--[[
simple function to pipe string.rep to templates.
]]
function str.rep( frame )
local repetitions = tonumber( frame.args[2] )
if not repetitions then
return str._error( 'function rep expects a number as second parameter, received "' .. ( frame.args[2] or '' ) .. '"' )
end
return string.rep( frame.args[1] or '', repetitions )
end
--[[
Helper function that populates the argument list given that user may need to use a mix of
named and unnamed parameters. This is relevant because named parameters are not
identical to unnamed parameters due to string trimming, and when dealing with strings
we sometimes want to either preserve or remove that whitespace depending on the application.
]]
function str._getParameters( frame_args, arg_list )
local new_args = {};
local index = 1;
local value;
for i,arg in ipairs( arg_list ) do
value = frame_args[arg]
if value == nil then
value = frame_args[index];
index = index + 1;
end
new_args[arg] = value;
end
return new_args;
end
--[[
Helper function to handle error messages.
]]
function str._error( error_str )
local frame = mw.getCurrentFrame();
local error_category = frame.args.error_category or 'Errors reported by Module String';
local ignore_errors = frame.args.ignore_errors or false;
local no_category = frame.args.no_category or false;
if str._getBoolean(ignore_errors) then
return '';
end
local error_str = '<strong class="error">String Module Error: ' .. error_str .. '</strong>';
if error_category ~= '' and not str._getBoolean( no_category ) then
error_str = '[[Category:' .. error_category .. ']]' .. error_str;
end
return error_str;
end
--[[
Helper Function to interpret boolean strings
]]
function str._getBoolean( boolean_str )
local boolean_value;
if type( boolean_str ) == 'string' then
boolean_str = boolean_str:lower();
if boolean_str == 'false' or boolean_str == 'no' or boolean_str == '0'
or boolean_str == '' then
boolean_value = false;
else
boolean_value = true;
end
elseif type( boolean_str ) == 'boolean' then
boolean_value = boolean_str;
else
error( 'No boolean value found' );
end
return boolean_value
end
--[[
Helper function that escapes all pattern characters so that they will be treated
as plain text.
]]
function str._escapePattern( pattern_str )
return mw.ustring.gsub( pattern_str, "([%(%)%.%%%+%-%*%?%[%^%$%]])", "%%%1" );
end
return str