Tcl Built-In Commands regexp(1T)
NAME
regexp - Match a regular expression against a string
SYNOPSIS
regexp ?switches? exp string ?matchVar? ?subMatchVar sub-
MatchVar ...?
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 expres-
sion matching is described in the resyntax 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 subexpres-
sion within exp, the next subMatchVar will contain the char-
acters 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 infor-
mation about the regular expression. The
first element of the list is a subexpression
count. The second element is a list of pro-
perty names that describe various attributes
of the regular expression. This switch is
primarily intended for debugging purposes.
-expanded Enables use of the expanded regular expres-
sion syntax where whitespace and comments are
ignored. This is the same as specifying the
(?x) embedded option (see the resyntax
manual page).
-indices Changes what is stored in the subMatchVars.
Instead of storing the matching characters
from string, each variable will contain a
list of two decimal strings giving the
indices in string of the first and last
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Tcl Built-In Commands regexp(1T)
characters in the matching range of charac-
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 `$' matches an empty string
before any newline in addition to its normal
function. This flag is equivalent to speci-
fying both -linestop and -lineanchor, or the
(?n) embedded option (see the resyntax
manual page).
-linestop Changes the behavior of `[^' bracket expres-
sions and `.' so that they stop at newlines.
This is the same as specifying the (?p)
embedded option (see the resyntax manual
page).
-lineanchor Changes the behavior of `^' and `$' (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 resyntax 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 variables,
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 vari-
ables 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 com-
mand will append the overall match data, plus
one element for each subexpression in the
regular expression. Examples are:
regexp -inline -- {\w(\w)} " inlined "
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Tcl Built-In Commands regexp(1T)
=> {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 expres-
sion 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 fol-
lowing this one will be treated as exp even
if it starts with a -.
If there are more subMatchVar's than parenthesized subex-
pressions within exp, or if a particular subexpression in
exp doesn't match the string (e.g. because it was in a por-
tion 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.
EXAMPLES
Find the first occurrence of a word starting with foo in a
string that is not actually an instance of foobar, and get
the letters following it up to the end of the word into a
variable:
regexp {\)(\w*)} $string -> restOfWord
Note that the whole matched substring has been placed in the
variable -> which is a name chosen to look nice given that
we are not actually interested in its contents.
Find the index of the word badger (in any case) within a
string and store that in the variable location:
regexp -indices {(?i)\} $string location
Count the number of octal digits in a string:
regexp -all {[0-7]} $string
List all words (consisting of all sequences of non-
whitespace characters) in a string:
regexp -all -inline {\S]} $string
SEE ALSO
resyntax(1T), regsub(1T)
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Tcl Built-In Commands regexp(1T)
KEYWORDS
match, regular expression, string
ATRIBUTES
See attributes(5) for descriptions of the following attri-
butes:
ATRIBUTE TYPE ATRIBUTE VALUE
Availability SUNWTcl
Interface Stability Uncommitted
NOTES
Source for Tcl is available on http:/opensolaris.org.
Tcl Last change: 8.3 4
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