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We are analyzing https://perldoc.perl.org/perlre.

Title:
perlre - Perl regular expressions - Perldoc Browser
Description:
No description found...
Website Age:
30 years and 1 months (reg. 1995-05-31).

Matching Content Categories {📚}

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Custom-built

No common CMS systems were detected on Perldoc.perl.org, but we identified it was custom coded using Bootstrap (CSS).

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What is the average monthly size of perldoc.perl.org audience?

🚄 Respectable Traffic: 10k - 20k visitors per month

Based on our best estimate, this website will receive around 14,120 visitors per month in the current month.

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How Does Perldoc.perl.org Make Money? {💸}

We're unsure how the site profits.

Not all websites focus on profit; some are designed to educate, connect people, or share useful tools. People create websites for numerous reasons. And this could be one such example. Perldoc.perl.org could be secretly minting cash, but we can't detect the process.

Keywords {🔍}

match, pattern, character, string, matches, perl, characters, regular, group, code, matching, modifier, capture, unicode, expression, foo, set, print, patterns, modifiers, rules, sequence, matched, note, number, construct, times, groups, backtracking, end, variable, special, class, locale, details, expressions, named, effect, script, inside, regex, parentheses, capturing, bracketed, metacharacters, doesnt, beginning, digits, classes, syntax,

Topics {✒️}

63 characters [a-za-z0-9_] support multi-byte locales logically-balancing closing brace simplify multi-line substitutions python/pcre-specific extensions pcre/python support length lookahead/lookbehind assertions ebcdic-based character sets ][_a-za-z0-9] experimental variable-length lookbehind double-quotish backslash interpolation pcre regex engines latin small letter platform-native matching rules higher-level loops preserve complete regular expression single multi-character construct customary unix meaning case-insensitive matching works multi byte locales stop user-supplied patterns mirror-image mate org/reports/tr36 brown fox jumps deeper underlying truth org/reports/tr39/ freely redistributable reimplementation handle variable lengths multi-character metapattern lexical variable declarations runtime variable interpolations fixed-width lookbehind latin capital letter github issue tracker extended regular expression /2019/02/variable-length-lookbehinds double-quotish context case-insensitive pattern matching mastering regular expressions demarcated variable names taint checking enabled bracketed character classes embedded pattern-match modifiers handle natural language extra letter doubles lower-level loops regular expression languages entire regular expression enforced script runs reject patterns appropriately

Questions {❓}

#[ \t]*(?
$pattern = "(?
'Y|' => qr/(?
'aaab' =~ /a+b?
'aaabaaab' =~ /a+b?
'foo' =~ m{ ( o?
('a' x 100)=~/(?
(It's possible to do things with named capture groups that would otherwise require (?
(One might mistakenly think that since the inner (?
(See "(?
(To avoid this cost while retaining the grouping behaviour, use the extended regular expression (?
) Similarly, doing something like (?
) and (?
) can't have a space between the "(", "?
/ ( a ) (?
/$foo$qr(?
/(x)(?
/AAA(?
/a(b|(?
/the (\S+)(?
12 (or higher), but see "Which character set modifier is in effect?
12" =~ /(?
14, a "^" (caret or circumflex accent) immediately after the "?
@fields = split(/\b(?
@matches = ( 'foo' =~ m{ o?
A fundamental feature of regular expression matching involves the notion called backtracking, which is currently used (when needed) by all regular non-possessive expression quantifiers, namely "*", *?
A powerful tool for optimizing such beasts is what is known as an "independent group", which does not backtrack (see "(?
A single /x tells the regular expression parser to ignore most whitespace that is neither backslashed nor within a bracketed character class, nor within the characters of a multi-character metapattern like (?
Also different is the treatment of capture buffers, unlike (?
Also see "Which character set modifier is in effect?
Also, modifiers are resolved at compile time, so constructs like (?
An effect similar to (?
Any letters between "?
At each position of the string the best match given by non-greedy ?
Consider the case where some patterns want to be case-sensitive and some do not: The case-insensitive ones merely need to include (?
Equivalent to (?
For a reference on how they are used, plus various examples of the same, see discussions of m//, s///, qr// and "?
For an example where side-effects of lookahead might have influenced the following match, see "(?
For example (?
For example /(?
For example /foo(?
For example, /(?
For example, /\w+(?
For example: ^(?
For various reasons \K may be significantly more efficient than the equivalent (?
Full syntax: (?
Full syntax: (?
Identical to (?
If you are looking for a "bar" that isn't preceded by a "foo", /(?
If you want it to match the minimum number of times possible, follow the quantifier with a "?
In fact, (?
In other words, a pattern such as ((?
In some cases, the use of (*PRUNE) can be replaced with a (?
Inside a (?
It behaves in exactly the same way as a (?
It is an error to refer to a name not defined by a (?
It is equivalent to (?
It is probably useful only when combined with (?
Like the "(?
Mnemonic for (?
NOTE: In order to make things easier for programmers with experience with the Python or PCRE regex engines the pattern (?
NOTE: In order to make things easier for programmers with experience with the Python or PCRE regex engines, the pattern (?
Nested (?
Note that (?
Notice that "hello" is only printed once, as when Perl sees that the sixth iteration of the outermost (?
On simple groups, such as the pattern (?
PAT*+ (?
PAT++ (?
PAT{min,max}+ (?
Same as S{0,1}?
See also "(?
See also (?
See the independent subexpression "(?
Similar in spirit to (?
Similar to (?
Similar to (R1), this predicate checks to see if we're executing directly inside of the leftmost group with a given name (this is the same logic used by (?
So ((?
So, doing something like (?
Such combinations can include alternatives, leading to a problem of choice: if we match a regular expression a|ab against "abc", will it match substring "a" or "ab"?
S{min,max}?
That's because the (?
The "*" quantifier is equivalent to {0,}, the "+" quantifier to {1,}, and the "?
The exact rules for how often (?
The first alternative includes everything from the last pattern delimiter ("(", "(?
The forms (?
The modifiers /imnsxadlup may also be embedded within the regular expression itself using the (?
The notation is (?
The o?
The two branches of a (?
Then it will try to match (?
This can be used to determine which branch of a pattern was matched without using a separate capture group for each branch, which in turn can result in a performance improvement, as perl cannot optimize /(?
This happens immediately, so $^R can be used from other (?
This is *exactly* the same as (?
This is because the nested (?
This is equivalent to putting ?
This modifier may be specified to be the default by use locale, but see "Which character set modifier is in effect?
This substitutes the question of "what is chosen?
Thus (?
Thus, for example, (?
Use a * instead of the ?
Use of the non-greedy modifier "?
What does this modifier do?
What's happening is that you've asked "Is it true that at the start of $x, following 0 or more non-digits, you have something that's not 123?
When inside of a nested pattern, such as recursion, or in a subpattern dynamically generated via (?
Which character set modifier is in effect?
X{min,max}?
You can use "(?
Aaabcdeeeee"=~/a(?
Aax" =~ /(?
Abc" =~ /(?
Good" =~ /g(?
Hello" =~ /(?
If ( /^\D*(?
My $parens = qr/(\((?
My $qr = qr/(?
M{ ( \( )?
Print "1: got $1\n" if $x =~ /^(ABC)(?
Print "2: got $1\n" if $y =~ /^(ABC)(?
Print "3: got $1\n" if $x =~ /^(\D*)(?
Print "4: got $1\n" if $y =~ /^(\D*)(?
Print "5: got $1\n" if $x =~ /^(\D*)(?
Print "6: got $1\n" if $y =~ /^(\D*)(?
Print "match: <$&>\n" while 'foo' =~ m{ o?
Qr/AAA(?
Qr/First part of a long regex(?
Qr/\(?
Qr/\p(?
Qr/abc(?
Qr/foo(?
S/abc(?
Say "axfoo"=~/(?
Say "yes: '$1-$2'" if "aayfoo"=~/(?
The pattern uses "(?
Which uses (?
{n,m}?
}) as a replacement for (?

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