1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
|
--- status: Rewritten July 2020
--- author(s): Dan, Mahrud
--- notes: functions below are all defined in regex.m2
doc ///
Key
match
(match, String, String)
(match, List, String)
[match, POSIX]
[match, Strategy]
"lastMatch"
Headline
regular expression matching
Usage
match(re, str)
match(patterns, str)
Inputs
re:String
a @TO2 {"regular expressions", "regular expression"}@ describing a pattern
str:String
a subject string to be searched
patterns:List
a list of regular expressions
POSIX=>Boolean
if true, interpret the @TT "re"@ using the POSIX Extended flavor, otherwise the Perl flavor
Strategy=>Function
logical quantifier for matching a list of patterns, typically @TO all@ or @TO any@
Outputs
:Boolean
whether the string @TT "str"@ is a match for the regular expression @TT "re"@,
or at least one of @TT "patterns"@ when @TT "Strategy => any"@ (default)
Consequences
Item
the variable @TO "lastMatch"@ is set to the value returned by @TO "regex"@ which is called by @TO "match"@.
Description
Text
For an introduction to regular expressions, see @TO "regular expressions"@.
Example
s = "three dogs, two catfishes, and a cat"
match("cat", s)
lastMatch
substring(first lastMatch, s)
match ("cats", s)
lastMatch
Text
The @TT "POSIX => true"@ option can be used to specify the POSIX Extended flavor for the regular
expression used to match. Note that only the Perl flavor allows the use of lookahead and lookbehinds.
Example
s = "catfish cat dog"
match("cat(?!fish)", s)
substring(lastMatch#0#0, lastMatch#0#1 + 4, s)
match("cat(?=fish)", s)
substring(lastMatch#0#0, lastMatch#0#1 + 4, s)
match("(?<!cat)fish", "cat catfish dog")
match("(?<!cat)fish", "cat swordfish dog")
Text
When the first input is a list, by default the output is true if @TT "str"@ is a match for at least
one of the given regular expressions.
Example
match({"Cat", "Dog"}, "CatDog")
match({"Cat", "Dog"}, "Catfish")
Text
Optionally, @TT "Strategy => all"@ indicates that the string should match every pattern in the list
to be a match.
Example
match({"Cat", "Dog"}, "CatDog", Strategy => all)
not match({"Cat", "Dog"}, "Catfish", Strategy => all)
Text
The @TT "Strategy"@ option is not used when the first input is not a list.
SeeAlso
"regular expressions"
"strings and nets"
regex
replace
substring
any
all
///
|
