源代码:
<?php // Positive numbers: echo substr("Hello world",0,10)." "; echo substr("Hello world",1,8)." "; echo substr("Hello world",0,5)." "; echo substr("Hello world",6,6)." "; echo " "; // Negative numbers: echo substr("Hello world",0,-1)." "; echo substr("Hello world",-10,-2)." "; echo substr("Hello world",0,-6)." "; echo substr("Hello world",-2-3)." "; ?>
运行结果：
Hello worl ello wor Hello world Hello worl ello wor Hello world