regexp(n) Tcl Built-In Commands regexp(n)
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NAME
regexp - Match a regular expression against a string
SYNOPSIS
regexp ?switches? exp string ?matchVar? ?subMatchVar subMatchVar ...?
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DESCRIPTION
Determines whether the regular expression exp matches part or all of string and returns 1 if it does,
0 if it doesn't, unless -inline is specified (see below). (Regular expression matching is described
in the re_syntax reference page.)
If additional arguments are specified after string then they are treated as the names of variables in
which to return information about which part(s) of string matched exp. MatchVar will be set to the
range of string that matched all of exp. The first subMatchVar will contain the characters in string
that matched the leftmost parenthesized subexpression within exp, the next subMatchVar will contain
the characters that matched the next parenthesized subexpression to the right in exp, and so on.
If the initial arguments to regexp start with - then they are treated as switches. The following
switches are currently supported:
-about Instead of attempting to match the regular expression, returns a list containing
information about the regular expression. The first element of the list is a subex-pression subexpression
pression count. The second element is a list of property names that describe various
attributes of the regular expression. This switch is primarily intended for debugging
purposes.
-expanded Enables use of the expanded regular expression syntax where whitespace and comments
are ignored. This is the same as specifying the (?x) embedded option (see the re_syn-tax re_syntax
tax manual page).
-indices Changes what is stored in the subMatchVars. Instead of storing the matching charac-ters characters
ters from string, each variable will contain a list of two decimal strings giving the
indices in string of the first and last characters in the matching range of charac-ters. characters.
ters.
-line Enables newline-sensitive matching. By default, newline is a completely ordinary
character with no special meaning. With this flag, `[^' bracket expressions and `.'
never match newline, `^' matches an empty string after any newline in addition to its
normal function, and `$' matches an empty string before any newline in addition to its
normal function. This flag is equivalent to specifying both -linestop and -linean-chor, -lineanchor,
chor, or the (?n) embedded option (see the re_syntax manual page).
-linestop Changes the behavior of `[^' bracket expressions and `.' so that they stop at new-lines. newlines.
lines. This is the same as specifying the (?p) embedded option (see the re_syntax
manual page).
-lineanchor Changes the behavior of `^' and `$' (the ``anchors'') so they match the beginning and
end of a line respectively. This is the same as specifying the (?w) embedded option
(see the re_syntax manual page).
-nocase Causes upper-case characters in string to be treated as lower case during the matching
process. |
-all ||
Causes the regular expression to be matched as many times as possible in the string, |
returning the total number of matches found. If this is specified with match vari- |
ables, they will contain information for the last match only. |
-inline ||
Causes the command to return, as a list, the data that would otherwise be placed in |
match variables. When using -inline, match variables may not be specified. If used |
with -all, the list will be concatenated at each iteration, such that a flat list is |
always returned. For each match iteration, the command will append the overall match |
data, plus one element for each subexpression in the regular expression. Examples |
are: |
regexp -inline -- {\w(\w)} " inlined " |
=> {in n} |
regexp -all -inline -- {\w(\w)} " inlined " |
=> {in n li i ne e} |
-start |
index | |
Specifies a character index offset into the string to start matching the regular |
expression at. When using this switch, `^' will not match the beginning of the line, |
and \A will still match the start of the string at index. If -indices is specified, |
the indices will be indexed starting from the absolute beginning of the input string. |
index will be constrained to the bounds of the input string.
-- Marks the end of switches. The argument following this one will be treated as exp
even if it starts with a -.
If there are more subMatchVar's than parenthesized subexpressions within exp, or if a particular
subexpression in exp doesn't match the string (e.g. because it was in a portion of the expression
that wasn't matched), then the corresponding subMatchVar will be set to ``-1 -1'' if -indices has
been specified or to an empty string otherwise.
SEE ALSO
re_syntax(n), regsub(n)
KEYWORDS
match, regular expression, string
Tcl 8.3 regexp(n)
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