Note: To test if a variable is a number or a numeric string (such as form input, which is always a string), you must use is_numeric().是什么意思_Note: To test if a variable is a number or a numeric string (such as form input, which is always a string), you must use is_numeric().在線(xiàn)翻譯_英語(yǔ)_讀音_用法_例句