Php Regular Expressions

Regular expressions are nothing more than a sequence or pattern of characters it. They provide the foundation for pattern matching functionality.

Using regular expression you can search a particular string inside a string, you can replace one string by another string and you can split a string into many chunks.

ereg()

The ereg() function searches a string specified by string for a string specified by the pattern, returning true if the pattern is found, and false otherwise.

Example

<?php
$date('Y-m-d');
 if(ereg("([0-9]{4})-([0-9]{1,2})-([0-9]{1,2})",$date,$regs)){
  echo "$regs[3].$regs[2].$regs[1]";
 }else{
  echo "invalide date formate";
 }
 // output 21.07.2019
?>

ereg_replace()

The ereg_replace() functions search for the string specified by pattern and replaces the pattern with a replacement if found.

eregi()

The eregi() function searches throughout a string specified by the pattern for a string specified by string. the search is not case-sensitive.

Example

<?php
if(eregi("z",$string)){
 echo "'$string' contains a 'z' or 'Z'";
// output z contains a 'z' or 'Z'
}
?>

ereg_replace()

The ereg_replace() function operates exactly like ereg_replace(), except that the search for pattern in a string is not case sensitive.

Example

<?php
$string = "This is a cow";
echo ereg_replace("is","was",$string);
//output This was a cow
?>

split()

The split() function will divide a string into various elements, the boundaries of each element based on the occurrence of pattern in a string.

Example

<?php
$date = "04/30/1973";
list($month,$day,$year) = split('/',$date);
echo 'Month :'.$month.'Day: '.$day.'Year: '.$year;
//output Month: 04 Day:30 Year: 1973
?>

spliti()

The spliti() function operates exactly in the same manner as its sibling split(), except that it is not case-sensitive.

sql_regcase()

The sql_regcase() function can be thought of as a utility function, converting each character in the input parameter string into a bracketed expression containing two characters.