PHP substr_count () function
Examples
Count the number of "world" appears in a string:
<?php
echo substr_count("Hello world. The world is nice","world");
?>
echo substr_count("Hello world. The world is nice","world");
?>
Running instance »
substr_count () function calculates the number of occurrences in the string substring.
Note: substring is case-sensitive.
Note: This function does not count overlapped substrings (see Example 2).
NOTE: If you start the argument plus length parameter is greater than the length of the string, the function will generate a warning (see Example 3).
grammar
substr_count( string,substring,start,length )
参数 | 描述 |
---|---|
string | 必需。规定要检查的字符串。 |
substring | 必需。规定要检索的字符串。 |
start | 可选。规定在字符串中何处开始搜索。 |
length | 可选。规定搜索的长度。 |
technical details
return value: | Returns the number of occurrences in the string substring. |
---|---|
PHP version: | 4+ |
Update log: | In PHP 5.1, add the start and length parameters. |
More examples
Example 1
Use all parameters:
<?php
$str = "This is nice";
echo strlen($str)."<br>"; // Using strlen() to return the string length
echo substr_count($str,"is")."<br>"; // The number of times "is" occurs in the string
echo substr_count($str,"is",2)."<br>"; // The string is now reduced to "is is PHP"
echo substr_count($str,"is",3)."<br>"; // The string is now reduced to "s is PHP"
echo substr_count($str,"is",3,3)."<br>"; // The string is now reduced to "s i"
?>
$str = "This is nice";
echo strlen($str)."<br>"; // Using strlen() to return the string length
echo substr_count($str,"is")."<br>"; // The number of times "is" occurs in the string
echo substr_count($str,"is",2)."<br>"; // The string is now reduced to "is is PHP"
echo substr_count($str,"is",3)."<br>"; // The string is now reduced to "s is PHP"
echo substr_count($str,"is",3,3)."<br>"; // The string is now reduced to "s i"
?>
Running instance »
Example 2
Overlapping substring:
<?php
$str = "abcabcab";
echo substr_count($str,"abcab"); // This function does not count overlapped substrings
?>
$str = "abcabcab";
echo substr_count($str,"abcab"); // This function does not count overlapped substrings
?>
Running instance »
Example 3
If start and length parameters over the length of the string, the function outputs a warning:
<?php
echo $str = "This is nice";
substr_count($str,"is",3,9);
?>
echo $str = "This is nice";
substr_count($str,"is",3,9);
?>
Due to the length of the value exceeds the length of the string (3 + 9 greater than 12). So it will output a warning.
PHP String Reference