What does isU of preg_match in php mean? preg_matchisu_PHP tutorial

What does isU of preg_match in php mean? preg_matchisu

isU means case split. Here, s does not include newlines and U reverses the number of matches. The value makes it not a default duplication, which is probably the case when we read the article.

/(.*)/isU after the regular expression, what does the "isU" parameter mean?

This is the modifier in regular expressions.

i searches for uppercase and lowercase letters simultaneously,

s is a dot (.) matching all characters, including newlines. If s is not set, newlines are not included.

U reverses the value of the number of matches so that it is not repeated by default, but becomes repeated when followed by "?"

Example

In preg_match compatible regular expression syntax, b represents word boundary

So: The following should be OK? ? ?

$a="test,admin,abc";
$b="te";
$exist=preg_match("/b{$b}b/",$a);
if($exist)
{
echo "存在";
}else
{
echo "不存在";
}

Look at the relevant instructions

Copy code The code is as follows:
int preg_match ( string pattern, string subject [, array matches [, int flags]] );

preg_match() returns the number of times pattern is matched. Either 0 times (no match) or 1 time, since preg_match() will stop searching after the first match. preg_match_all(), on the contrary, will search until the end of subject. preg_match() returns false on error.

Example:

<&#63;php
$a = "abcdefgabcdefaaag";
preg_match('|abc([a-z]+)g|isu',$a,$out1);
preg_match_all('|abc([s]+)g|isu',$a,$out2);
echo "<pre class="brush:php;toolbar:false">";
print_r($out1);
print_r($out2);
echo "

"; ?>

Writing:

The difference between using double quotes and single quotes

<&#63;php
preg_match_all("/href="(.*)"/isu",$contents,$out);
preg_match_all('|href="(.*)"|isu',$contents,$out);
&#63;>

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