Home > Article > Backend Development > Analysis of substr() function in PHP (with detailed code explanation)
In the actual combat of PHP
, we often need to parse the URL
string and intercept the fragments we need, PHP
provides us with the substr()
function, we can easily obtain the data we need. This article will take you to take a look at PHP
##substr()Function.
substr() function:
substr ( string $string , int $start , int $length = ? )
1. If the parameters are all non-negative integers
<?php echo substr('php.cn is all right', 1); echo "<br>"; echo substr('php.cn is all right', 1, 3); echo "<br>"; echo substr('php.cn is all right', 0, 4); echo "<br>"; echo substr('php.cn is all right', 0, 8); ?>
输出: hp.cn is all right hp. php. php.cn i
2.If $ start appears as a negative integer
<?php echo substr("php.cn is all right", -1); echo "<br>"; echo substr("php.cn is all right", -2); echo "<br>"; echo substr("php.cn is all right", -3, 1); ?>
输出: t ht g
3. If $length appears as a negative integer
<?php echo substr("php.cn is all right", 0,-1); echo "<br>"; echo substr("php.cn is all right",2, -1); echo "<br>"; echo substr("php.cn is all right",4, 4); echo "<br>"; echo substr("php.cn is all right",-3, -1); ?>
输出:php.cn is all righ p.cn is all righ cn i gh
Recommended: 《2021 PHP Summary of interview questions (collection)》《php video tutorial》
The above is the detailed content of Analysis of substr() function in PHP (with detailed code explanation). For more information, please follow other related articles on the PHP Chinese website!