PHP Manual
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# strpos

(PHP 3, PHP 4, PHP 5)

strpos -- Find position of first occurrence of a string

## Description

int strpos ( string haystack, mixed needle [, int offset] )

Returns the numeric position of the first occurrence of needle in the haystack string. Unlike the strrpos(), this function can take a full string as the needle parameter and the entire string will be used.

If needle is not found, strpos() will return boolean `FALSE`.

警告
本函数可能返回布尔值 `FALSE`，但也可能返回一个与 `FALSE` 等值的非布尔值，例如 0 或者 ""。请参阅布尔类型章节以获取更多信息。应使用 === 运算符来测试本函数的返回值。

> 注: 该函数可安全用于二进制对象。

例子 1. strpos() examples

`<?php
$mystring = 'abc';
$findme = 'a';
$pos = strpos($mystring, $findme);
// Note our use of ===. Simply == would not work as expected
// because the position of 'a' was the 0th (first) character.
if ($pos === false) {
echo "The string '$findme' was not found in the string '$mystring'";
} else {
echo "The string '$findme' was found in the string '$mystring'";
echo " and exists at position $pos";
}
// We can search for the character, ignoring anything before the offset
$newstring = 'abcdef abcdef';
$pos = strpos($newstring, 'a', 1); // $pos = 7, not 0
?>`

If needle is not a string, it is converted to an integer and applied as the ordinal value of a character.

The optional offset parameter allows you to specify which character in haystack to start searching. The position returned is still relative to the beginning of haystack.

See also strrpos(), stripos(), strripos(), strrchr(), substr(), stristr(), and strstr().

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