Anchors
Basic metacharacters
Character classes
Comments
Control and code
Grouping
Look around
Mode modifiers
Quantifiers
Specific characters
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Anchors are used to tie (part of) an expression to a certain position.
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Item
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Matches at:
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^
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Start of a string. If used in multiline mode also matches beginning of each line, (i.e. after a newline).
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$
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End of a string. If used in multiline mode also matches end of each line, (i.e. before a newline).
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\A
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Start of a string.
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\b
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Word boundary.
This is the position between an \W and \w or between \w and \W . (In a character class \b represents a backspace.)
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\B
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Any position that is not a word boundary.
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\z
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End of string.
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\Z
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End of string if the string does not end with a newline. If it ends with a newline \Z matches just before that.
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