php截取字符串函数分享
author:一佰互联 2019-04-28   click:151

经常看到有新手问PHP有没有类似asp的left函数或right函数,实现截取某字符串左边或右边开始N个字符的函数。答案当然是有的。PHP中的substr函数就可以做的到,只不过PHP把二个函数合二为一了,这里再给大家分享一个更加优秀的截取字符串的函数。

复制代码 代码如下:/**     * 方法库-截取字符串-【该函数作者未知】     * @param string  $string 字符串       * @param int     $length 字符长度     * @param string  $dot    截取后是否添加...     * @param string  $charset编码     * @return string     */    public function cutstr($string, $length, $dot = " ...", $charset = "utf-8") {        if (strlen($string) <= $length) {            return $string;        }        $string = str_replace(array("&", """, "<", ">"), array("&", """, "<", ">"), $string);        $strcut = "";        if (strtolower($charset) == "utf-8") {            $n = $tn = $noc = 0;            while ($n < strlen($string)) {                $t = ord($string[$n]);                //ASCIIֵ                if($t == 9 || $t == 10 || (32 <= $t && $t <= 126)) {                    $tn = 1; $n++; $noc++;                } elseif (194 <= $t && $t <= 223) {                    $tn = 2; $n += 2; $noc += 2;                } elseif (224 <= $t && $t < 239) {                    $tn = 3; $n += 3; $noc += 2;                } elseif (240 <= $t && $t <= 247) {                    $tn = 4; $n += 4; $noc += 2;                } elseif (248 <= $t && $t <= 251) {                    $tn = 5; $n += 5; $noc += 2;                } elseif ($t == 252 || $t == 253) {                    $tn = 6; $n += 6; $noc += 2;                } else {                    $n++;                }                if($noc >= $length) {                    break;                }            }            if ($noc > $length) {                $n -= $tn;            }            $strcut = substr($string, 0, $n);        } else {            for ($i = 0; $i < $length; $i++) {                $strcut .= ord($string[$i]) > 127 ? $string[$i].$string[++$i] : $string[$i];            }        }        $strcut = str_replace(array("&", """, "<", ">"), array("&", """, "<", ">"), $strcut);        return $strcut.$dot;    }

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