Python 字符串内置函数(四)

# 4.类型判断# isalnum()函数检测字符串是否只由字母和数字组成。s = "this2009";  # 字符中没有空格print(s.isalnum()) # 结果：True# isalpha()函数检测字符串是否只由字母组成。s = "runoob";print(s.isalpha()) # 结果：True# isdecimal()函数检查字符串是否只包含十进制字符。这种方法只存在于unicode对象。s1 = u"this2009";print(s1.isdecimal()) # 结果：Falses2 = u"23443434";print(s2.isdecimal())# 结果：True# isdigit()函数检测字符串是否只由数字组成。s1 = "123456";  # Only digit in this stringprint(s1.isdigit()) # 结果：Trues2 = "this is string example....wow!!!";print(s2.isdigit()) # 结果：False# isidentifier()函数检查字符串是不是有效标识符s = "Demo"print(s.isidentifier()) # 结果：True# islower()函数检测字符串是否由小写字母组成。s1 = "THIS is string example....wow!!!";print(s1.islower()) # 结果：Falses2 = "this is string example....wow!!!";print(s2.islower())# 结果：True# isnumeric()函数检测字符串是否只由数字组成。这种方法是只针对unicode对象。s1 = u"this2009";print(s1.isnumeric()) # 结果：Falses2 = u"23443434";print(s2.isnumeric()) # 结果：True# isspace()函数检测字符串是否只由空格组成。s1 = "       "; # 结果：Trueprint(s1.isspace())s2 = "This is string example....wow!!!";print(s2.isspace()) # 结果：False# istitle()函数检测字符串中全部的单词拼写首字母是否为大写，且其余字母为小写。s1 = "This Is String Example...Wow!!!";print(s1.istitle()) # 结果：Trues2 = "This is string example....wow!!!";print(s2.istitle()) # 结果：False# isupper()函数检测字符串中全部的字母是否都为大写。s1 = "THIS IS STRING EXAMPLE....WOW!!!";print(s1.isupper()) # 结果：Trues2 = "THIS is string example....wow!!!";print(s2.isupper()) # 结果：False