PHP substr_count() 函数

PHP String Functions

实例

计算 "Shanghai" 在字符串中出现的次数：

<?php
echo substr_count("I love Shanghai. Shanghai is the biggest city in china.","Shanghai");
?>

Run Instance

substr_count() 函数计算子串在字符串中出现的次数。

注释：子串是区分大小写的。

注释：该函数不计数重叠的子串（参见例子 2）。

注释：If start 参数加上 length 参数大于字符串长度，则该函数生成一个警告（参见例子 3）。

语法

substr_count(string,substring,start,length)
参数 描述
string 必需。规定被检查的字符串。
substring 必需。规定要搜索的字符串。
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 times the substring appears in the string.
PHP Version: 4+
Update Log: In PHP 5.1, a new start and length Parameters.

More Examples

Example 1

Use all parameters:

<?php
$str = "This is nice";
echo strlen($str)."<br>"; // Use strlen() to return the length of the string
echo substr_count($str,"is")."<br>"; // The number of occurrences of "is" in the string
echo substr_count($str,"is",2)."<br>"; // The string is reduced to "is is nice"
echo substr_count($str,"is",3)."<br>"; // The string is reduced to "s is nice"
echo substr_count($str,"is",3,3)."<br>"; // The string is reduced to "s i"
?>

Run Instance

Example 2

Overlapping Substring:

<?php
$str = "abcabcab";
echo substr_count($str,"abcab"); // This function does not count overlapping substrings
?>

Run Instance

Example 3

If start and length If the parameters exceed the length of the string, the function will output a warning:

<?php
echo $str = "This is nice";
substr_count($str,"is",3,9);
?>

Because the length value exceeds the length of the string (3 + 9 is greater than 12), a warning will be output when used.

PHP String Functions