PHP Regular Expression Function Learning Summary _php Tutorial

What are the PHP regular expression functions? So what exactly does the PHP regular expression function represent? What is the specific usage? Let us introduce to you. PHP regular expressions are primarily used for the processing of complex strings. The main PHP regular expression functions are as follows:

Ereg ()

Ereg_replace ()

Eregi ()

Eregi_replace ()

Split ()

PHP Regular Expression function usage induction:

(1) Ereg,eregi

This is the regular expression matching function, the former is case-sensitive, the latter is irrelevant.

Usage:

Ereg (regular expression, string, [match partial array name]); Regular expressions in PHP3.0 are broadly similar to those used in grep.

(2) Ereg_replace,eregi_replace

These are replacement functions.

Usage:

Ereg_replace (Regular expression, substitution string, original string);

There is a strtr in the string handler function, which is a "translation" function, similar to the tr/.../.../in Perl,

Usage:

STRTR (String, "from", "to");

For example:

STRTR ("Aaabb", "AB", "CD") returns "CCCDD".

(3) Split

Similar to the EXPLODE function, but this time it is possible to split a string where it matches a regular expression.

Usage:

Split (regular expression, string, [how many items before removal]);

These functions use a regular string as the first argument. PHP uses the extended regular string defined by the POSIX 1003.2 standard. To see the full description of POSIX regular expressions see the man page under the Regex directory in the PHP package.

PHP Regular Expression Function application example:

 
 

  
  

  
Ereg ("abc",$string); 
  
  

  
/ * Returns true if "abc" is
  
  

  
found anywhere in $string. * *  
  
  

  

  
  

  
Ereg ("^abc",$string); 
  
  

  
/ * Returns true if "abc" is
  
  

  
found at the beginning of $string. * *  
  
  

  

  
  

  
Ereg ("abc$",$string); 
  
  

  
/ * Returns true if "abc" is
  
  

  
found at the end of $string. * *  
  
  

  

  
  

  
Eregi ("(ozilla.[ 23]| MSIE.3) ",$HTTP _user_agent); 
  
  

  
/ * Returns True if client browser
  
  

  
is Netscape 2, 3 or MSIE 3. * /  
  
  

  

  
  

  
Ereg ([[: alnum:]]+) ([alnum:]]+)
  
  

  
([[: alnum:]]+) ", $string , $regs ); 
  
  

  
/ * Places Three space separated words
  
  

  
Into $regs [1], $regs [2] and $regs [3]. * /  
  
  

  

  
  

  
ereg_replace ("^","",$string); 
  
  

  
/ * Put a tag at the beginning of $string. * /  
  
  

  

  
  

  
ereg_replace ("$","",$string); 
  
  

  
/ * Put a tag at the end of $string. * /  
  
  

  

  
  

  
ereg_replace ("","",$string); 
  
  

  
/ * Get rid of any carriage
  
  

  
return characters in $string. * /  
 
 

The relevant contents of the PHP Regular expression function are introduced to you, and hopefully it will help you understand and learn about the PHP regular expression functions.

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