php截取字串函數，php自訂字串截取方法

/** * 方法庫-截取字串 * @param string $string 字串 * @param int$length 字元長度 * @param string $dot 截取後是否添加... * @param string $charset編碼 * @return string */ public function cutstr($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[$n]); //ASCII? if($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; } 複製代碼 例2，php檢測字串是否存在： /** * 方法庫-字串是否存在 * @param string $str :字元或字串 * @param string $string :字串 * @return string 例子: $str='34' $string='1234' 返回 TRUE */ public function is_str_exist($str, $string) { $string = (string) $string; $str = (string) $str; return strstr($string,$str)===false ? false : true; } 複製代碼

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