แม่แบบ:Str left

คู่มือการใช้งานแม่แบบ[ดู] [แก้] [ประวัติ] [ล้างแคช]

Usage[แก้]

{{Str left|<string>|<count>}}

Gives the <count> substring of characters from the start of the trimmed string (the substring has length <count>).

If <count> is invalid, empty or zero, an empty string is returned. If undefined, it defaults to 1.

Limitations[แก้]

Length to 500: The maximum substring stops at 500 long, yet gives no error message. Only 500 characters can be extracted even if the <string> is longer.
Inexpensive (uses no other templates).

Examples[แก้]

{{ Str left | Lorem ipsum dolor sit amet | 10 }} → Lorem ipsu
{{ Str left | Lorem ipsum dolor sit amet | 1 }} → L
{{ Str left | Lorem ipsum dolor sit amet | 0 }} →
{{ Str left | Lorem ipsum dolor sit amet | }} →
{{ Str left | Lorem ipsum dolor sit amet }} → L
{{ Str left | Lorem ipsum dolor sit amet | 40 }} → Lorem ipsum dolor sit ametLorem ipsum do
{{ Str left | àçé | 2 }} → àç
This example is demonstrating the safety of this template with the UTF-8 encoding (this should work now) :

Examples of limitations[แก้]

All the limitations of use for this template and shown below are caused by the current implementation of the {{padleft:}} parser function used in this template, which does not filter its third parameter containing the characters used for padding a string to the specified length (it currently counts incorrectly the characters to extract from the padding string, and incorrectly measures its effective length; in addition this parameter is limited to 500 bytes).

The following examples are demonstrating that this template is not safe with character entity references found in its string parameter :

{{ Str left | a c | 3 }} → a&n
This should display "a c", but the named character entity was partially truncated, leaving no length available for the final "c".
{{ Str left | aBc | 3 }} → a&#
This should display "abc", but the named character entity was partially truncated, leaving no length available for the final "c".
{{ Str left | a c | 3 }} → a c
The result is correct, as expected.
{{ Str left | a c | 3 }} → a&#
This last example should be equivalent to the previous one, but it is not.

The following example shows that the presence of some wiki markup that should be transparent and ignored, does not allow this template to work as expected (the nowiki section is replaced by a unique index string in the effective runtime value of the parameter ; this unique (43-bytes long) string starts by a control character (which will be finally filtered out from the generated HTML page if it remains in the result of this template), followed by "UNIQ" and some unique sequence and terminated by "QINU" and a final control character ; it is partially visible below, because the unique string is not complete after truncation, and then cannot be eliminated from the output in the first two lines):

{{ Str left | a<nowiki/>bc | 3 }} → abc
It effectively returns 3 bytes, but the \x07 (BELL) control in the second position is stripped out when generating the HTML displayed here.
{{ Str left | a<nowiki/>bc | 43 }} → abcabcabcabcabcabcabcabcabcabcabcabcabcabca
It effectively returns 43 bytes, but the \x07 (BELL) control in the second position is stripped out when generating the HTML displayed here, and the final \x07 was truncated
{{ Str left | a<nowiki/>bc | 44 }} → abcabcabcabcabcabcabcabcabcabcabcabcabcabcab
It effectively returns 44 bytes, but the complete 43-bytes sequence is filtered out from the output wiki code when generating the final HTML, so there just remains the first leading "a" character .
{{ Str left | a<nowiki/>bc | 45 }} → abcabcabcabcabcabcabcabcabcabcabcabcabcabcabc

On the opposite, the HTML comments, and the "noinclude", "includeonly" and "onlyinclude" wiki markup tags are safe, because they are preprocessed in template parameters, before including it and substituing parameters:

{{ Str left | a<noinclude/>bc | 3 }} → abc
{{ Str left | abc | 3 }} → abc

Note also that the specified length will cause the input string to be padded by repeating it, it this length is larger than the input string length:

{{ Str left | Abc. | 10 }} → Abc.Abc.Ab

ด ค ก แม่แบบจัดการสายอักขระ
ตั้งแต่เดือนกุมภาพันธ์ พ.ศ. 2556 แม่แบบเหล่านี้ได้ใช้ Module เพื่อเพิ่มประสิทธิภาพ
Trim by counting	{{Str mid}} – To return a substring, specified by its position and length. {{Trunc}} – To trim down to a specified number of characters. {{Str left}} – To trim down to a specified number of characters, or duplicate the string to a specified number. {{Str crop}} – To crop a specified number of characters off the end. {{Chop head and tail}} – To crop a specified number of characters off the beginning and end. {{Str right}} – To trim the first specified number of characters. {{Str rightc}} – To return a number of characters from the end, returns a parameter if the string is empty. {{Str rightmost}} – To trim down to the last specified number of characters. {{Str sub old}} – To trim down to a specified number, starting at a given number from the left. {{Str sub new}} – Select a substr based on starting and ending index. {{Str index}} – Returns a given character from a string, but not accented letters.
Trim by checking	{{Trim}} – To trim any leading or trailing whitespace ({{Strip whitespace}} does so too, but is less effective) {{First word}} – To trim down to the first space. {{Remove first word}} – To remove anything before the first space. {{Str letter/trim}} – To trim down to the beginning letters. {{Str number/trim}} – To trim down to the beginning numbers.
Insert strings	{{Repeat}} – Repeat character string n times {{Replace}} – Returns the string, after replacing all occurrences of a specified string with another string. {{Strloc insert}} – Inserts a string at character location strloc, or appends if strloc<=0. {{Strloc prefix}} – Extracts string prefix up to location strloc, or whole string if strloc<=0. {{Str rep}} – Returns the string, after replacing the first occurrence of a specified string with another string.
Length	{{Str len}} – Returns a string's length. {{iflenge}} – IF LENgth Greater then or Equal to. {{Str ≥ len}} – To check if a string is "longer or equally long" or "shorter" than a given length. {{Str ≤ len}} – To check if a string is "shorter or equally long" or "longer" than a given length. {{Str ≠ len}} – To check if a string is "not equal" or "equal" to a given length. {{Str ≤ ≥ len}} – To check if a string is "shorter", "equal", or "longer" than a given length.
Analyse string	{{Str endswith}} – To check if a string ends with a given string. {{Strfind}} หรือ {{Strfind short}} – คืนค่าตำแหน่งของข้อความย่อยในข้อความ {{Str find}} – คืนค่าตำแหน่งของข้อความย่อยในข้อความ (ล้าสมัย) {{Str find0}} – Zero-based substring search. {{Str sub find}} – Searches a substring in a string at the given offset. {{ASCII code}} – Returns the ASCII value of a single character. {{Str letter}} – Returns the number of letters that begin a string. {{Str number}} – Returns the number of numbers that begin a string. {{Str gtr str}} – Compares two strings for alphabetical order, and returns a value accordingly.
Trim, dedicated	{{WikiProjectbasename}} - Removes "WikiProject" from a pagename {{Remove unranked}} - Removes the string "unranked_" from the left of a string (taxonomy). {{Ship prefix}} – Returns the length of a ship name prefix, if listed (ship names). {{Title without disambig}} – To trim off any parenthesis text at the end of a string (disambiguation). {{Title disambig text}} – Returns text in parenthesis at the end of a string (disambiguation). {{Unlink}} – Removes wikilink brackets (wikicode).
Technical developments	Module:String mw:Help:Magic words – About `{{padleft:\|}}`. mw:Help:Extension:ParserFunctions – About `{{#titleparts:\|}}, {{#expr:\|}}, {{#ifeq:\|}},` etc.
Category:String manipulation templates m:Category:String templates commons:Category:String manipulation templates

Usage[แก้]

Limitations[แก้]

Examples[แก้]

Examples of limitations[แก้]

See also[แก้]