This article introduces regular expressions in php, and I would like to share them with you. Friends who are interested can take a look at
- ##Separator
- Forward slash (/)
- hash symbol (#)
##Negative symbol (~)
Universal Atom
##\d- Decimal 0 to 9
\D- Negate decimal numbers from 0 to 9
\w- Numbers and letters underline
\W- In addition to numbers and letters underline
\s- White space characters
\S- Except whitespace characters
##metacharacters
. Matches any single character except newline characters (\n, \r) -
* Matches the previous subexpression zero or more times-
+ Matches the previous subexpression one or more times-
? Matches the previous subexpression zero or one time -
{n} n is a non Negative integer, matches a certain number of n times -
##{n,}
n is a non-negative integer, matches at least n times
-
{n,m}
m and n are both non-negative integers, where n <= m. Match at least n times and match at most m times
-
^
Match the beginning of the input string
-
$
Matches the end position of the input string
-
[]
represents matching an element in a set, such as [abc] represents matching a or b or c
-
()
Match the content within () and get
##Pattern modifier
-
i
Case-insensitive
m
Treat the string as multiple lines, no matter which line it is, it can match
s
Treat the string as a single line, and the newline character is treated as an ordinary character
e
e Use with function preg_replace() (php7 to cancel)
U
U Only match the most recent string, no repeated matches
x
x Ignore whitespace in the pattern
A
Force matching from the beginning of the target string
D
If you use $ to limit the ending character, no newline at the end is allowed
u
The pattern string is treated as UTF-8 (can be used to match Chinese)
To be continued……………………
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