源代码:
<?php // Positive numbers: echo substr("Hello world",10)." "; echo substr("Hello world",1)." "; echo substr("Hello world",3)." "; echo substr("Hello world",7)." "; echo " "; // Negative numbers: echo substr("Hello world",-1)." "; echo substr("Hello world",-10)." "; echo substr("Hello world",-8)." "; echo substr("Hello world",-4)." "; ?>
运行结果：
d ello world lo world orld d ello world lo world orld