python中str函数isdigit、isdecimal、isnumeric的区别

num = "1" #unicode () # True () # True () # True num = "1" # 全角 () # True () # True () # True num = b"1" # byte () # True () # AttributeError 'bytes' object has no attribute 'isdecimal' () # AttributeError 'bytes' object has no attribute 'isnumeric' num = "IV" # 罗马数字 () # True () # False () # True num = "四" # 汉字 () # False () # False () # True =================== isdigit() True: Unicode数字，byte数字（单字节），全角数字（双字节），罗马数字 False: 汉字数字 Error: 无 isdecimal() True: Unicode数字，，全角数字（双字节） False: 罗马数字，汉字数字 Error: byte数字（单字节） isnumeric() True: Unicode数字，全角数字（双字节），罗马数字，汉字数字 False: 无 Error: byte数字（单字节） ================ import unicodedata ("2") # 2 ("2") # 2 ("2") # 2.0 ("2") # 2 ("2") # 2 ("2") # 2.0 (b"3") # TypeError: must be str, not bytes (b"3") # TypeError: must be str, not bytes (b"3") # TypeError: must be str, not bytes ("Ⅷ") # ValueError: not a digit ("Ⅷ") # ValueError: not a decimal ("Ⅷ") # 8.0 ("四") # ValueError: not a digit ("四") # ValueError: not a decimal ("四") # 4.0 #"〇","零","一","壱","二","弐","三","参","四","五","六","七","八","九","十","廿","卅","卌","百","千","万","万","亿"