[TOC] ### 靜態化屬性 因為靜態化后,執行過程中只初始化一次 ``` function send_http_status($code) { static $_status = array( // Informational 1xx 100 => 'Continue', 101 => 'Switching Protocols', // Success 2xx 200 => 'OK', 201 => 'Created', 202 => 'Accepted', 203 => 'Non-Authoritative Information', ... ... ); } ``` ### 遞增一個未預定義的局部變量要比遞增一個預定義的局部變量慢9至10倍 ### 檢測字符串長度 ``` if (strlen($foo) < 5) { echo "Foo is too short"; } if (!isset($foo{5})) { echo "Foo is too short"; } //更優 ```