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{{Documentation subpage}}
{{lua|Module:String}}
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=== Usage ===
Characters in the source string are counted: the first is index {{code|1=1}}, the last one is index {{code|length of string}}. The substring requested can be defined by these two indexes. Also, the substring can be defined by one index, and the substring length. The options are:
<nowiki> {{str mid|<string>|<index of first character>|<length of substring>|<index of last character>}} </nowiki>
It returns a part of the <string>, starting with character on position ''index'', length <sublength>, last character returned is end index.
*<nowiki>{{str mid|Abcdefghijklmnopqrstuvwxyz|5|3}}</nowiki> &rarr; {{str mid|Abcdefghijklmnopqrstuvwxyz|5|3}}

If parameter 2 is omitted, start is from character 1:
*<nowiki>{{str mid|Abcdefghijklmnopqrstuvwxyz||5}}</nowiki> &rarr; {{str mid|Abcdefghijklmnopqrstuvwxyz||5}}

If parameter 3 is omitted, the whole rest of the string is returned:
*<nowiki>{{str mid|Abcdefghijklmnopqrstuvwxyz|15}}</nowiki> &rarr; {{str mid|Abcdefghijklmnopqrstuvwxyz|15}}

=== Counting from the end ===
By entering a ''negative value'', the index is counted ''from the end'':
*<nowiki>{{str mid|Abcdefghijklmnopqrstuvwxyz|-7|4}}</nowiki> &rarr; {{str mid|Abcdefghijklmnopqrstuvwxyz|-7|4}}
*<nowiki>{{str mid|Abcdefghijklmnopqrstuvwxyz|-7}}</nowiki> &rarr; {{str mid|Abcdefghijklmnopqrstuvwxyz|-7}}

=== Instead if substring length, use index for last character ===
By using parameter {{para|4|''n''}}, a number, you do not ask for substring length, but the last character (as counted from the start of the input string):
*<nowiki>{{str mid|Abcdefghijklmnopqrstuvwxyz|5||7}}</nowiki> &rarr; {{str mid|Abcdefghijklmnopqrstuvwxyz|5||7}}

===Spaces are kept===
In the returned substring, spaces are kept:
*<nowiki>>{{str mid|I like this.|2|6}}<</nowiki> &rarr; >{{str mid|I like this,|2|6}}<
But the input string is trimmed:
*<nowiki>>{{str mid|   I like this.   |2|6}}<</nowiki> &rarr; >{{str mid|   I like this.   |2|6}}<

===Error messages===
When the ranges (either param2 or the substring length) is out impossible in the string, an error is returned:
*<nowiki>{{str mid|Abcdefghijklmnopqrstuvwxyz|30}}</nowiki> &rarr; {{str mid|Abcdefghijklmnopqrstuvwxyz|30|ignore errors=false|no category=true}}
*<nowiki>{{str mid|Abcdefghijklmnopqrstuvwxyz|0|45}}</nowiki> &rarr; {{str mid|Abcdefghijklmnopqrstuvwxyz|5|45|ignore errors=false|no category=true}}
The error can be suppressed by using {{para|ignore errors|true}}. A blank (empty string) will be returned:
*<nowiki>{{str mid|Abcdefghijklmnopqrstuvwxyz|0|45|ignore errors=true}}</nowiki> &rarr; {{str mid|Abcdefghijklmnopqrstuvwxyz|5|45|ignore errors=true}}

====Error category====
* {{para|no category|true}} switches off category adding.
* {{para|error category|<nowiki>[[Category:Your category name]]</nowiki>}} sets the category to be added when in case of an error.<br/>
::Default is [[:Category:Errors reported by Module String]].

=== See also ===
{{string-handling templates}}


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