python中str函数isdigit、isdecimal、isnumeric的区别

num = "1"  #unicode
num.isdigit() # True
num.isdecimal() # True
num.isnumeric() # True num = "1" # 全角
num.isdigit() # True
num.isdecimal() # True
num.isnumeric() # True num = b"1" # byte
num.isdigit() # True
num.isdecimal() # AttributeError 'bytes' object has no attribute 'isdecimal'
num.isnumeric() # AttributeError 'bytes' object has no attribute 'isnumeric' num = "IV" # 罗马数字
num.isdigit() # True
num.isdecimal() # False
num.isnumeric() # True num = "四" # 汉字
num.isdigit() # False
num.isdecimal() # False
num.isnumeric() # 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 unicodedata.digit("2") # 2
unicodedata.decimal("2") # 2
unicodedata.numeric("2") # 2.0 unicodedata.digit("2") # 2
unicodedata.decimal("2") # 2
unicodedata.numeric("2") # 2.0 unicodedata.digit(b"3") # TypeError: must be str, not bytes
unicodedata.decimal(b"3") # TypeError: must be str, not bytes
unicodedata.numeric(b"3") # TypeError: must be str, not bytes unicodedata.digit("Ⅷ") # ValueError: not a digit
unicodedata.decimal("Ⅷ") # ValueError: not a decimal
unicodedata.numeric("Ⅷ") # 8.0 unicodedata.digit("四") # ValueError: not a digit
unicodedata.decimal("四") # ValueError: not a decimal
unicodedata.numeric("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"
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