Using strpos() and strrpos() Functions to Detect Substrings in PHP

Method 1: Detect using strpos() function

strpos()

function can find the position of the first occurrence of a substring within another string (case-sensitive).

If the specified character exists, it returns the position of the first occurrence; otherwise it returns FALSE.

Note: String positions start at 0, not 1.

Example:

<?php
header('content-type:text/html;charset=utf-8');   
$findme = 'C';
$mystring1 = 'xyz';
$mystring2 = 'ABC';
$pos1 = strpos($mystring1, $findme);
$pos2 = strpos($mystring2, $findme);
var_dump($pos1);
var_dump($pos2);
if($pos1){
 echo $mystring1." 中指定字符 C<br>";
}else{
 echo $mystring1." 中不包含指定字符 C<br>";
}
if($pos2){
 echo $mystring2." 指定字符 C<br>";
}else{
 echo $mystring2." 不包含指定字符 C<br>";
}
?>

Method 2: Detect using strrpos() function

strrpos()

function can find the position of the last occurrence of a substring within another string (case-sensitive).

If the specified character exists, it returns the position of the last occurrence; otherwise it returns FALSE.

Example:

<?php
header('content-type:text/html;charset=utf-8');   
$findme = 'c';
$mystring1 = 'xyzc';
$mystring2 = 'ABC';
$pos1 = strrpos($mystring1, $findme);
$pos2 = strrpos($mystring2, $findme);
var_dump($pos1);
var_dump($pos2);
if($pos1){
 echo $mystring1." 中指定字符 c<br>";
}else{
 echo $mystring1." 中不包含指定字符 c<br>";
}
if($pos2){
 echo $mystring2." 指定字符 c<br>";
}else{
 echo $mystring2." 不包含指定字符 c<br>";
}
?>

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