获取字符串php的最后一个字符
substr("testers", -1); // returns "s"
php获取字符串的第一个字符
$firstStringCharacter = substr("hello", 0, 1);
php获取字符串的前5个字符
$result = substr("Hello How are you", 0, 5); //first 5 chars "Hello"
php修剪字符串到长度
<?php
echo substr('abcdef', 1); // bcdef
echo substr('abcdef', 1, 3); // bcd
echo substr('abcdef', 0, 4); // abcd
echo substr('abcdef', 0, 8); // abcdef
echo substr('abcdef', -1, 1); // f
// Accessing single characters in a string
// can also be achieved using "square brackets"
$string = 'abcdef';