Difference between revisions of "IDE regular expressions"
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They are pretty similar to Perl regular expression syntax. | They are pretty similar to Perl regular expression syntax. | ||
| − | + | Metacharacters: | |
| + | \ Quote the next metacharacter | ||
| + | ^ Match the beginning of the line | ||
| + | . Match any character (except newline). Example: 'a.c' matches 'abc', 'aBC', 'axc', 'a3c', 'a$c', etc. | ||
| + | $ Match the end of the line (or before newline at the end) | ||
| + | | Alternation | ||
| + | () Grouping. For example: (abc)+ matches 'abc' or 'abcabc' or 'abcabcabc' etc. | ||
| + | [] Character class | ||
| − | + | Quantifiers: | |
| + | * Match 0 or more times | ||
| + | + Match 1 or more times | ||
| + | ? Match 1 or 0 times | ||
| + | {n} Match exactly n times | ||
| + | {n,} Match at least n times | ||
| + | {n,m} Match at least n but not more than m times | ||
| − | + | Curly brackets in any other context is treated as a regular character. | |
| + | The ``*'' is equivalent to {0,}, the ``+'' to {1,} and the ``?'' to {0,1}. | ||
| − | + | By default, a quantifier is ''greedy'', that means, it will match as many times as possible. To match the minimum number of times possible, append a ``?''. | |
| + | |||
| + | *? Match 0 or more times | ||
| + | +? Match 1 or more times | ||
| + | ?? Match 0 or 1 time | ||
| + | {n}? Match exactly n times | ||
| + | {n,}? Match at least n times | ||
| + | {n,m}? Match at least n but not more than m times | ||
== Simple Syntax == | == Simple Syntax == | ||
Revision as of 11:31, 26 July 2006
Normal regular expression
They are pretty similar to Perl regular expression syntax.
Metacharacters:
\ Quote the next metacharacter ^ Match the beginning of the line . Match any character (except newline). Example: 'a.c' matches 'abc', 'aBC', 'axc', 'a3c', 'a$c', etc. $ Match the end of the line (or before newline at the end) | Alternation () Grouping. For example: (abc)+ matches 'abc' or 'abcabc' or 'abcabcabc' etc. [] Character class
Quantifiers:
* Match 0 or more times
+ Match 1 or more times
? Match 1 or 0 times
{n} Match exactly n times
{n,} Match at least n times
{n,m} Match at least n but not more than m times
Curly brackets in any other context is treated as a regular character. The ``* is equivalent to {0,}, the ``+ to {1,} and the ``? to {0,1}.
By default, a quantifier is greedy, that means, it will match as many times as possible. To match the minimum number of times possible, append a ``?.
*? Match 0 or more times
+? Match 1 or more times
?? Match 0 or 1 time
{n}? Match exactly n times
{n,}? Match at least n times
{n,m}? Match at least n but not more than m times
Simple Syntax
Some IDE dialogs provide a checkbox to enable 'simple syntax'. These regular expressions are shorter for common file name filters.
Technically it does this:
The following characters are replaced with . -> \. * -> .* ? -> . , -> | ; -> | Finally enclose by ^( )$
Search and Replace with regular expressions
The find dialogs support regular expressions for finding and replacing. For example:
- Find expression: a(.*)c
- Replace expression: A$1C
- Text: 'abc aLazc'
The $1 will be replaced with the found text, that matches the first bracket.
- Result: 'AbC ALazC'
