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strpos

(PHP 4, PHP 5)

strpos — Find position of first occurrence of a string

说明

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() before PHP 5, this function can take a full string as the needle parameter and the entire string will be used.

参数

haystack

needle

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

offset

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 .

返回值

Returns the position as an integer. If needle is not found, strpos() will return boolean FALSE.

Warning

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。

范例

Example#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
?>

注释

Note: 本函数可安全用于二进制对象。


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