Preg_match() usage of php regular expression_PHP tutorial

Using preg_match(), we can complete the rule matching of strings. The preg_match() function returns 1 if a match is found, 0 otherwise. There is an optional third parameter that allows you to store the matched parts in an array. This feature can become very useful when validating data.

The code is as follows

Copy code

代码如下	复制代码
// 模式定界符后面的 "i" 表示不区分大小写字母的搜索 if (preg_match ("/php/i", "PHP is the web scripting language of choice.")) { print "A match was found."; } else { print "A match was not found."; } ?>

// The "i" after the pattern delimiter indicates a case-insensitive search

代码如下	复制代码
//需要匹配的字符串。date函数返回当前时间。 "现在时刻：2012-04-20 07:31 am" $content = "现在时刻：".date("Y-m-d h:i a"); //匹配日期和时间. if (preg_match ("/d{4}-d{2}-d{2} d{2}:d{2} [ap]m/", $content, $m)) { echo "匹配的时间是：" .$m[0]. "n"; //"2012-04-20 07:31 am" } //分别取得日期和时间 if (preg_match ("/([d-]{10}) ([d:]{5} [ap]m)/", $content, $m)) { echo "当前日期是：" .$m[1]. "n"; //"2012-04-20" echo "当前时间是：" .$m[2]. "n"; //"07:31 am" } ?>

if (preg_match ("/php/i", "PHP is the web scripting language of choice.")) {

print "A match was found.";

} else {

代码如下	复制代码
$str = file_get_contents('http://www.google.com'); preg_match('/ /', $str, $arr); echo $arr[1]; ?>

print "A match was not found.";

}

代码如下	复制代码
preg_match("/^(http://)?([^/]+)/i", "http://www.bKjia.c0m/index.html", $matches); $host = $matches[2]; // 从主机名中取得后面两段 preg_match("/[^./]+.[^./]+$/", $host, $matches); echo "domain name is: {$matches[0]}n"; ?>

?>

Get the current time

The code is as follows

Copy code

//The string that needs to be matched. The date function returns the current time. "Current time: 2012-04-20 07:31 am" $content = "Current time:".date("Y-m-d h:i a"); //Match date and time. if (preg_match ("/d{4}-d{2}-d{2} d{2}:d{2} [ap]m/", $content, $m)) { echo "The matching time is:" .$m[0]. "n"; //"2012-04-20 07:31 am" } //Get the date and time respectively if (preg_match ("/([d-]{10}) ([d:]{5} [ap]m)/", $content, $m)) { echo "The current date is:" .$m[1]. "n"; //"2012-04-20" echo "The current time is:" .$m[2]. "n"; //"07:31 am" } ?>

This example will verify that the email address is in the correct format. Now let's take a look at the various rules represented by this regular expression. Get Google homepage title For example, if you want to get the title content of Google homepage, the code is as follows:

The code is as follows	Copy code
$str = file_get_contents('http://www.google.com'); preg_match('//', $str, $arr); echo $arr[1]; ?>

Get domain name from URL

The code is as follows	Copy code
preg_match("/^(http://)?([^/]+)/i", "http://www.bKjia.c0m/index.html", $matches); $host = $matches[2]; // Get the next two segments from the host name preg_match("/[^./]+.[^./]+$/", $host, $matches); echo "domain name is: {$matches[0]}n"; ?>

preg_match($pattern,$string,$matcher) where $pattern corresponds to /^(http://)?([^/]+)/i, $string is http://www.php. net/index.html, $match is the matched result.

If matches is provided, it will be populated with the results of the search. $matches[0] will contain text that matches the entire pattern, $matches[1] will contain text that matches the first captured subpattern in parentheses, and so on.

$matches[0] will contain text that matches the entire pattern. Let’s use spring_r to print out the first $matches:

[0] => http://www.bKjia.c0m [1] => http://

The code is as follows

代码如下	复制代码
Array (  [0] => http://www.bKjia.c0m  [1] => http://  [2] => www.bKjia.c0m )

Copy code

Array (

[2] => www.bKjia.c0m )

$matches[0] will contain text that matches the entire pattern, and $matches[1] will contain text that matches the subpattern within the first captured parentheses. In regular expressions, () represents pattern: match pattern and get this match. The matches obtained can be obtained from the generated Matches collection, using the SubMatches collection in VBScript or the $0…$9 properties in JScript. That is to say, the value with subscript 1 in the array is the value in the first () of /^(http://)?([^/]+)/i in the regular expression! The value of array subscript 2 is deduced by analogy. http://www.bkjia.com/PHPjc/628982.html

www.bkjia.comtrue

http: //www.bkjia.com/PHPjc/628982.htmlTechArticleUsing preg_match(), we can complete the rule matching of strings. The preg_match() function returns 1 if a match is found, 0 otherwise. There is also an optional third parameter that allows...