Home  >  Article  >  Backend Development  >  Regular expressions for review of PHP knowledge points_PHP tutorial

Regular expressions for review of PHP knowledge points_PHP tutorial

WBOY
WBOYOriginal
2016-07-13 17:48:271037browse

Previous article http://www.BkJia.com/kf/201202/118458.html

//Technical knowledge of regular expressions


// []Define character set and example [a-z] [A-Z] [0-9] [frnt]


//locator ^[A-Z][0-9]$ starts and ends


//Quantifier * + ? {n} {m,n} {n.} refers to the number of repetitions


//Select|


//Printable characters: The characters represented by 33-127 in ASCII are the symbols we can see. Space, delete, carriage return, cancel, etc. are typically non-printable characters


//POSOX regular expression
//Commonly used functions
echo "
";
$b4 = "abc";
$pattern = "[[:alpha:]]";
echo ereg($pattern,$b4);
//Output 1
//eregi() unsigned





$b7 = "asd&ass@ass&adfdf";

$pattern1 = "&";
$pattern2 = "[&@]";
print_r(split($pattern1,$b7));
print_r(split($pattern2,$b7));


echo "
";
$b8 = "helloworld";
$pattern3 = "world";
$replacement1 = "persion";
echo ereg_replace($pattern3,$replacement1,$b8);


echo "
";
echo sql_regcase("abcdefg");
//Output: [Aa][Bb][Cc][Dd][Ee][Ff][Gg]


//Perl regular expression perl is an additional extension based on posix support d digits D non-digits s blank S non-blank w alphanumeric symbols underline W non-alphanumeric symbols underline

//Commonly used function array preg_grep (string pattern, array input)
echo "
";
$w1 = array("adad","adad4","asda","1asf3","sdfs");
$fl_array = preg_grep ("/^D{1,}$/", $w1);//The emphasis here is {1,} instead of {1.} in posix
print_r($fl_array);


echo "
";
echo preg_match ("/a/","abc");
//Output 1


echo "
";
//b represents the boundary of the word
if (preg_match ("/bwebb/i", "PHP is the web scripting language of choice.")) {
Print "A match was found.";
} else {
Print "A match was not found.";
}


if (preg_match ("/bwebb/i", "PHP is the website scripting language of choice.")) {
Print "A match was found.";
} else {
Print "A match was not found.";
}
//Especially used when matching email addresses


echo "
";
$pattern5 = "/[*]+/";
$w3 = "aaa***bbb*ccc";
print_r(preg_split($pattern5,$w3));


echo "
";
$pattern6 = "/world/";
$content2 = "girl";
$tre = "hello world";
echo preg_replace($pattern6,$content2,$tre);


//string preg_quote ( string str [, string delimiter] ) escape
echo "
";
$keywords = "$40 for a g3/400";
$keywords = preg_quote ($keywords, "/");//If the / here is not added, the / in g3/400 will not be escaped;
echo $keywords;

Excerpted from kaituozhe345’s column

www.bkjia.comtruehttp: //www.bkjia.com/PHPjc/478415.htmlTechArticlePart 1 http://www.2cto.com/kf/201202/118458.html //Regular expression Technical knowledge // [] Define character set and example [a-z] [A-Z] [0-9] [frnt] // Locator ^[A-Z][0-9]$ begins and ends //amount...
Statement:
The content of this article is voluntarily contributed by netizens, and the copyright belongs to the original author. This site does not assume corresponding legal responsibility. If you find any content suspected of plagiarism or infringement, please contact admin@php.cn