• Regular Expression Cheat Sheet Pdf
• Posix Extended Regular Expression Cheat Sheet

PHP PCRE Cheat Sheet Functions pregmatch(pattern, subject, submatches) pregmatchall(pattern, subject, submatches) pregreplace(pattern, replacement, subject) pregreplacecallback(pattern, callback, subject) preggrep(pattern, array) pregsplit(pattern, subject) Base Character Classes w Any “word” character (a-z 0-9 ). Git log -G regex - git log -S - Useful options:-i, -regexp-ignore-case Match the regular expression limiting patterns without regard to letter case.E, -extended-regexp Consider the limiting patterns to be extended regular expressions instead of the default basic regular expressions.

The POSIX-Extended regular expression syntax is supported by the POSIX C regular expression API's, and variations are used by the utilities egrep and awk. You can construct POSIX extended regular expressions in Boost.Regex by passing the flag extended to the regex constructor, for example:

In POSIX-Extended regular expressions, all characters match themselves except for the following special characters:

Run grep with extended regular expressions.-i Ignore case (ie uppercase, lowercase letters).-v Return all lines which don't match the pattern.-w Select only matches that form whole words.-c Print a count of matching lines. Can be combined with the -v option to print a count of non matchine lines.-l Print the name of each file which contains a match. Regular Expressions / Regex Cheat Sheet Special Characters in Regular Expressions & their meanings. Character Meaning Example. See also: Regular Expression Character Classes CheatSheet. This is a work in progress - Questions, comments, criticism, or requests can be directed Here. This page provides an overall cheat sheet of all the capabilities of RegExp syntax by aggregating the content of the articles in the RegExp guide. If you need more information on a specific topic, please follow the link on the corresponding heading to access the full article or head to the guide.

The single character '.' when used outside of a character set will match any single character except:

• The NULL character when the flag match_no_dot_null is passed to the matching algorithms.
• The newline character when the flag match_not_dot_newline is passed to the matching algorithms.

A '^' character shall match the start of a line when used as the first character of an expression, or the first character of a sub-expression.

A '$' character shall match the end of a line when used as the last character of an expression, or the last character of a sub-expression.

A section beginning ( and ending ) acts as a marked sub-expression. Whatever matched the sub-expression is split out in a separate field by the matching algorithms. Marked sub-expressions can also repeated, or referred to by a back-reference.

Any atom (a single character, a marked sub-expression, or a character class) can be repeated with the *, +, ?, and {} operators.

The * operator will match the preceding atom zero or more times, for example the expression a*b will match any of the following:

The + operator will match the preceding atom one or more times, for example the expression a+b will match any of the following:

But will not match:

The ? operator will match the preceding atom zero or one times, for example the expression ca?b will match any of the following:

But will not match:

An atom can also be repeated with a bounded repeat:

a{n} Matches 'a' repeated exactly n times.

a{n,} Matches 'a' repeated n or more times.

a{n,m} Matches 'a' repeated between n and m times inclusive.

For example:

Will match either of:

But neither of:

It is an error to use a repeat operator, if the preceding construct can not be repeated, for example:

Will raise an error, as there is nothing for the * operator to be applied to.

An escape character followed by a digit n, where n is in the range 1-9, matches the same string that was matched by sub-expression n. For example the expression:

Will match the string:

But not the string:

Caution
The POSIX standard does not support back-references for 'extended' regular expressions, this is a compatible extension to that standard.

The | operator will match either of its arguments, so for example: abc|def will match either 'abc' or 'def'.

Parenthesis can be used to group alternations, for example: ab(d|ef) will match either of 'abd' or 'abef'.

A character set is a bracket-expression starting with [ and ending with ], it defines a set of characters, and matches any single character that is a member of that set.

A bracket expression may contain any combination of the following:

For example [abc], will match any of the characters 'a', 'b', or 'c'.

For example [a-c] will match any single character in the range 'a' to 'c'. By default, for POSIX-Extended regular expressions, a character x is within the range y to z, if it collates within that range; this results in locale specific behavior . This behavior can be turned off by unsetting the collateoption flag - in which case whether a character appears within a range is determined by comparing the code points of the characters only.

If the bracket-expression begins with the ^ character, then it matches the complement of the characters it contains, for example [^a-c] matches any character that is not in the range a-c.

An expression of the form [[:name:]] matches the named character class 'name', for example [[:lower:]] matches any lower case character. See character class names.

An expression of the form [[.col.] matches the collating element col. A collating element is any single character, or any sequence of characters that collates as a single unit. Collating elements may also be used as the end point of a range, for example: [[.ae.]-c] matches the character sequence 'ae', plus any single character in the range 'ae'-c, assuming that 'ae' is treated as a single collating element in the current locale.

Collating elements may be used in place of escapes (which are not normally allowed inside character sets), for example [[.^.]abc] would match either one of the characters 'abc^'.

As an extension, a collating element may also be specified via its symbolic name, for example:

matches a NUL character.

An expression of the form [[=col=]], matches any character or collating element whose primary sort key is the same as that for collating element col, as with colating elements the name col may be a symbolic name. A primary sort key is one that ignores case, accentation, or locale-specific tailorings; so for example [[=a=]] matches any of the characters: a, À, Á, Â, Ã, Ä, Å, A, à, á, â, ã, ä and å. Unfortunately implementation of this is reliant on the platform's collation and localisation support; this feature can not be relied upon to work portably across all platforms, or even all locales on one platform.

All of the above can be combined in one character set declaration, for example: [[:digit:]a-c[.NUL.]].

The POSIX standard defines no escape sequences for POSIX-Extended regular expressions, except that:

• Any special character preceded by an escape shall match itself.
• The effect of any ordinary character being preceded by an escape is undefined.
• An escape inside a character class declaration shall match itself: in other words the escape character is not 'special' inside a character class declaration; so [^] will match either a literal ' or a '^'.

However, that's rather restrictive, so the following standard-compatible extensions are also supported by Boost.Regex:

The following escape sequences are all synonyms for single characters:

Escape	Character
a	'a'
e	0x1B
f	f
Calservice.net. n	n
r	r
t	t
v	v
b	b (but only inside a character class declaration).
cX	An ASCII escape sequence - the character whose code point is X % 32
xdd	A hexadecimal escape sequence - matches the single character whose code point is 0xdd.
x{dddd}	A hexadecimal escape sequence - matches the single character whose code point is 0xdddd.
0ddd	An octal escape sequence - matches the single character whose code point is 0ddd.
N{Name}	Matches the single character which has the symbolic name name. For example N{newline} matches the single character n.

Any escaped character x, if x is the name of a character class shall match any character that is a member of that class, and any escaped character X, if x is the name of a character class, shall match any character not in that class.

The following are supported by default:

Escape sequence	Equivalent to
d	[[:digit:]]
l	[[:lower:]]
s	[[:space:]]
u	[[:upper:]]
w	[[:word:]]
D	[^[:digit:]]
L	[^[:lower:]]
S	[^[:space:]]
U	[^[:upper:]]
W	[^[:word:]]

The character property names in the following table are all equivalent to the names used in character classes.

Form	Description	Equivalent character set form
pX	Matches any character that has the property X.	[[:X:]]
p{Name}	Matches any character that has the property Name.	[[:Name:]]
PX	Matches any character that does not have the property X.	[^[:X:]]
P{Name}	Matches any character that does not have the property Name.	[^[:Name:]]

For example pd matches any 'digit' character, as does p{digit}.

The following escape sequences match the boundaries of words:

Escape	Meaning
<	Matches the start of a word.
>	Matches the end of a word.
b	Matches a word boundary (the start or end of a word).
B	Matches only when not at a word boundary.

The following match only at buffer boundaries: a 'buffer' in this context is the whole of the input text that is being matched against (note that ^ and $ may match embedded newlines within the text).

Escape	Meaning
`	Matches at the start of a buffer only.
'	Matches at the end of a buffer only.
A	Matches at the start of a buffer only (the same as `).
z	Matches at the end of a buffer only (the same as ').
Z	Matches an optional sequence of newlines at the end of a buffer: equivalent to the regular expression n*z

The sequence G matches only at the end of the last match found, or at the start of the text being matched if no previous match was found. This escape useful if you're iterating over the matches contained within a text, and you want each subsequence match to start where the last one ended.

The escape sequence Q begins a 'quoted sequence': all the subsequent characters are treated as literals, until either the end of the regular expression or E is found. For example the expression: Q*+Ea+ would match either of:

Escape	Meaning
C	Matches a single code point: in Boost regex this has exactly the same effect as a '.' operator.
X	Matches a combining character sequence: that is any non-combining character followed by a sequence of zero or more combining characters.

Any other escape sequence matches the character that is escaped, for example @ matches a literal '@'.

The order of precedence for of operators is as follows:

1. Collation-related bracket symbols [][::][.]
2. Escaped characters
3. Character set (bracket expression) []
4. Grouping ()
5. Single-character-ERE duplication *+?{m,n}
6. Concatenation
7. Anchoring ^$
8. Alternation |

When there is more that one way to match a regular expression, the 'best' possible match is obtained using the leftmost-longest rule.

When an expression is compiled with the flag egrep set, then the expression is treated as a newline separated list of POSIX-Extended expressions, a match is found if any of the expressions in the list match, for example:

will match either of the POSIX-Basic expressions 'abc' or 'def'.

As its name suggests, this behavior is consistent with the Unix utility egrep, and with grep when used with the -E option.

Torrent client software. In addition to the POSIX-Extended features the escape character is special inside a character class declaration.

In addition, some escape sequences that are not defined as part of POSIX-Extended specification are required to be supported - however Boost.Regex supports these by default anyway.

There are a variety of flags that may be combined with the extended and egrep options when constructing the regular expression, in particular note that the newline_alt option alters the syntax, while the collate, nosubs and icase options modify how the case and locale sensitivity are to be applied.

regex in notepad++

Searching a string using the ‘Find‘ or ‘Find & Replace‘ function in text editors highlights the relevant match (e.g. searching ‘le‘ highlights it inside words such as ‘apple‘, ‘please’ etc). However, some advanced editors such as Notepad++ (I mention Notepad++ in my examples since its my favourite so far!) supports the use of regex, which recently saved me hours of manually replacing strings and numeric values in files containing HTML and JacaScript codes.

Regular Expression Cheat Sheet Pdf

Regex characters can be used to create advanced matching criteria. The following table introduces some of them with practical examples. But before starting make sure that you change the Search Mode from Normal to Regular expression in your Find or Find & Replace dialogue box.

• [ ]

The square brackets can be used to match ONE of multiple characters. For instance, [abc] matches any of the characters a, b or c. Hence, b[eo]n will match words like ben and bon, but not been or beon. Ranges can also be used, [a-z] is any lower case character and so on.

• ^

The caret can be used inside the square brackets to exclude characters from the match. For instance, hell[^o] means the string ‘hell’ will be ignored if followed by the letter ‘o’. Another example is [^A-Za-z] which will exclude all alphabetic characters.
However, if not placed inside a set, ^ can be used to matches the start of a line.

• $

This matches the end of a line.

• .

The period or dot matches any character.

• d

Matches any single digit.

• w

Matches any single alphanumeric characters or underscore.

• s

Matches whitespaces including tabs and line breaks.

• *

The asterisk or star sign matches 0 or more times. For example, Ba*m matches Bm , Bam , Baam etc.

• +

The plus sign matches 1 or more times. For example, lo+l matches lol , lool , loool etc.

• <

Matches the start of a word. For example, < directly followed by 'sh' matches 'she' but does not matches 'wish'.

• >

Matches the end of a word. For example, sh> matches ‘wish’ and does not matches ‘she’.

• ( )

The round brackets can be used in the Find & Replace function to tag a match. tagged matches can then be used in replace with 1, 2 etc.
For example, If you write 123xxxRRR in the search and 1231HHH in the ‘Replace with’ filed, the result will be: 123xxxHHH.

The backslash can be used to escape regex characters. For example to match 1+1=2, the correct regex is 1+1=2. Otherwise, the plus sign will have a special meaning.

Further, the following two examples should be giving you a better idea of how to use regex in your editor:

Posix Extended Regular Expression Cheat Sheet

• Find: Win([0-9]+) Replace with: Windows1

Will search for strings like Win2000, Win2003 and changes them to Windows2000, Windows2003…

• Find: [a-z]+(dd)> Replace with: Windows1

Will search for all alphanumerics followed by 2 digits only at the end such as Win98 and Win07 and changes them to Windows98, Windows07…