PHP中substr函数字符串截取用法分析,phpsubstr
PHP中substr函数字符串截取用法分析,phpsubstr
本文实例讲述了PHP中substr函数字符串截取用法。分享给大家供大家参考,具体如下:
PHP中substr函数定义如下:
substr(string,start,length)
参数说明如下:
string 必需。规定要返回其中一部分的字符串。
start
必需。规定在字符串的何处开始。
正数 - 在字符串的指定位置开始
负数 - 在从字符串结尾开始的指定位置开始
0 - 在字符串中的第一个字符处开始
length
可选。规定被返回字符串的长度。默认是直到字符串的结尾。
正数 - 从 start 参数所在的位置返回的长度
负数 - 从字符串末端返回的长度
示例代码如下:
<?php echo substr("Welcome to www.jb51.net!",0); //原样输出,不截取 echo "<br>"; echo substr("Welcome to www.jb51.net!",4,14); //从第4个字符开始连续截取14个字符 echo "<br>"; echo substr("Welcome to www.jb51.net!",-4,4); //从倒数第4个开始截取4个字符 echo "<br>"; echo substr("Welcome to www.jb51.net!",0,-4); //从第一个字符开始截取,截取到倒数第4个字符 ?>
运行结果如下:
Welcome to www.jb51.net! ome to www.jb5 net! Welcome to www.jb51.
希望本文所述对大家PHP程序设计有所帮助。
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