Mô đun:String

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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 Thể loại: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 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.

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 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.

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 }}Lỗi mô đun String: Không tìm thấy kết quả
  • {{#invoke:String|match|s= abc |pattern= %d |nomatch= No numeric characters in string }} → No numeric characters in string

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|find|source_string|target_string}}

OR

{{#invoke:String|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

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 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 }} → 0
  • {{#invoke:String|find|source= abc123def }} → 0
  • {{#invoke:String|find| abc123def |123}} → 5
  • {{#invoke:String|find|source= abc123def |target= 123 }} → 4
  • {{#invoke:String|find| abc123def |%d|3|false}} → 5
  • {{#invoke:String|find|source= abc123def |target= %d |start= 3 |plain= false }} → 4

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 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|N}}" → " abcNdef456 "
  • "{{#invoke:String|replace|source= abc123def456 |pattern= 123 |replace= N }}" → "abcNdef456"
  • "{{#invoke:String|replace| abc123def456 |%d+|N|1|false}}" → " abcNdef456 "
  • "{{#invoke:String|replace|source= abc123def456 |pattern= %d+ |replace= N |count=1 |plain= false }}" → "abcNdef456"
  • "{{#invoke:String|replace|source= abc123def456 |pattern= %d+ |replace= N |plain= false }}" → "abcNdefN"

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 "

See also



--[=[  

Mô đun này nhằm cung cấp các hàm chuỗi cơ bản.

Phần nhiều hàm này cho phép gọi với các tham số có tên, các tham số không có
tên, hoặc pha trộn cả hai kiểu. Nếu sử dụng các tham số có tên, MediaWiki tự
động bỏ qua khoảng cách đằng truớc và đằng sau tham số. Tùy cách sử dụng, bạn có
thể cần giữ hoặc bỏ qua khoảng cách này.

Các tùy chọn toàn cục:
    ignore_errors: Nếu là 'true' hoặc 1, bất cứ trạng thái lỗi nào sẽ cho ra
        chuỗi rỗng thay vì thông báo lỗi.
    
    error_category: Nếu xuất hiện lỗi, trang được tự động xếp vào thể loại này
        và thông báo lỗi sẽ được hiển thị. Thể loại mặc định là
        [[Thể loại:Trang gây lỗi trong mô đun String]].
        
    no_category: Nếu là 'true' hoặc 1, trang không được tự động xếp vào thể loại
        khi xuất hiện lỗi.

Các trường hợp kiểm thử đơn vị cho mô đun này có sẵn tại [[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( 'Chỉ số chuỗi con nằm ngoài phạm vi' );
    end
    if j < i then
        return str._error( 'Chỉ số chuỗi con bị lộn nguợc' );
    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( 'Chuỗi đích rỗng' );
    end
    if pattern == '' then
        return str._error( 'Chuỗi mẫu rỗng' );
    end
    if math.abs(start) < 1 or math.abs(start) > mw.ustring.len( s ) then
        return str._error( 'Chỉ số bắt đầu nằm ngoài phạm vi' );
    end
    if match_index == 0 then
        return str._error( 'Chỉ số trùng khớp nằm ngoài phạm vi' );
    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( 'Không tìm thấy kết quả' );
        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( 'Chỉ số chuỗi nằm ngoài phạm vi' );
    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( 'tham số thứ 2 của hàm rep có giá trị “' .. ( frame.args[2] or '' ) .. '” thay cho số' )
    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 'Trang gây lỗi trong mô đun 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">Lỗi mô đun String: ' .. error_str .. '</strong>';
    if error_category ~= '' and not str._getBoolean( no_category ) then
        error_str = '[[Thể loại:' .. 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( 'Không tìm thấy giá trị luận lý' );
    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

function str.decimalPoint(frame)
	local args = frame.args
    if not args[1] then
        args = frame:getParent().args
    end
    return str._decimalPoint(args[1])
end

function str._decimalPoint(number_str)
	local decimal
	
	number_str = number_str:gsub("[Ee]%-?%d+$", "")
	number_str = number_str:gsub("^%-", "")
	
	if number_str:match("^[^,.]*$") then return "," end
	
	decimal = number_str:match("^0?([.,])%d+$")
	if decimal then return decimal end
	decimal = number_str:match("%d([.,])%d?%d?$") or number_str:match("%d([.,])%d%d%d%d+$")
	if decimal then return decimal end
	if number_str:match("^%d?%d?%d?[,.]%d%d%d$") then return end
	
	if number_str:match("%.%d+%.") then return "," end
	if number_str:match("%,%d+,") then return "." end
end

return str