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PHP5中文手册

strtok

(PHP 4, PHP 5)

strtok — Tokenize string

Description

string strtok ( string $str , string $token )

strtok() splits a string (str ) into smaller strings (tokens), with each token being delimited by any character from token . That is, if you have a string like "This is an example string" you could tokenize this string into its individual words by using the space character as the token.

Example#1 strtok() example

<?php
$string 
"This is\tan example\nstring";
/* Use tab and newline as tokenizing characters as well  */
$tok strtok($string" \n\t");

while (
$tok !== false) {
    echo 
"Word=$tok<br />";
    
$tok strtok(" \n\t");
}
?>

Note that only the first call to strtok uses the string argument. Every subsequent call to strtok only needs the token to use, as it keeps track of where it is in the current string. To start over, or to tokenize a new string you simply call strtok with the string argument again to initialize it. Note that you may put multiple tokens in the token parameter. The string will be tokenized when any one of the characters in the argument are found.

The behavior when an empty part was found changed with PHP 4.1.0. The old behavior returned an empty string, while the new, correct, behavior simply skips the part of the string:

Example#2 Old strtok() behavior

<?php
$first_token  
strtok('/something''/');
$second_token strtok('/');
var_dump($first_token$second_token);
?>

Output:

    string(0) ""
    string(9) "something"

Example#3 New strtok() behavior

<?php
$first_token  
strtok('/something''/');
$second_token strtok('/');
var_dump($first_token$second_token);
?>

Output:

    string(9) "something"
    bool(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。

See also split() and explode().