python 判断字符串是不是字母 python 判断字符串是不是字母

python\u5224\u65ad\u5b57\u7b26\u662f\u4e0d\u662f\u5b57\u6bcd

s\u4e3a\u5b57\u7b26\u4e32
s.isalnum() \u6240\u6709\u5b57\u7b26\u90fd\u662f\u6570\u5b57\u6216\u8005\u5b57\u6bcd\uff0c\u4e3a\u771f\u8fd4\u56de Ture\uff0c\u5426\u5219\u8fd4\u56de False\u3002\uff08\u91cd\u70b9\uff0c\u8fd9\u662f\u5b57\u6bcd\u6570\u5b57\u4e00\u8d77\u5224\u65ad\u7684\uff01\uff01\uff09
s.isalpha() \u6240\u6709\u5b57\u7b26\u90fd\u662f\u5b57\u6bcd\uff0c\u4e3a\u771f\u8fd4\u56de Ture\uff0c\u5426\u5219\u8fd4\u56de False\u3002\uff08\u53ea\u5224\u65ad\u5b57\u6bcd\uff09
s.isdigit() \u6240\u6709\u5b57\u7b26\u90fd\u662f\u6570\u5b57\uff0c\u4e3a\u771f\u8fd4\u56de Ture\uff0c\u5426\u5219\u8fd4\u56de False\u3002\uff08\u53ea\u5224\u65ad\u6570\u5b57\uff09
s.islower() \u6240\u6709\u5b57\u7b26\u90fd\u662f\u5c0f\u5199\uff0c\u4e3a\u771f\u8fd4\u56de Ture\uff0c\u5426\u5219\u8fd4\u56de False\u3002
s.isupper() \u6240\u6709\u5b57\u7b26\u90fd\u662f\u5927\u5199\uff0c\u4e3a\u771f\u8fd4\u56de Ture\uff0c\u5426\u5219\u8fd4\u56de False\u3002
s.istitle() \u6240\u6709\u5355\u8bcd\u90fd\u662f\u9996\u5b57\u6bcd\u5927\u5199\uff0c\u4e3a\u771f\u8fd4\u56de Ture\uff0c\u5426\u5219\u8fd4\u56de False\u3002
s.isspace() \u6240\u6709\u5b57\u7b26\u90fd\u662f\u7a7a\u767d\u5b57\u7b26\uff0c\u4e3a\u771f\u8fd4\u56de Ture\uff0c\u5426\u5219\u8fd4\u56de False\u3002

import
stringnums
=
string.digitsdef
check(a):
if
type(a)
is
not
str:
return
false
else:
for
i
in
a:
if
i
not
in
nums:
return
false
return
true\u4f7f\u7528\u5b57\u7b26\u4e32\u6a21\u5757\u91cc\u9762\u7684\u5b8f\u5b9a\u4e49digits\uff0c\u5b83\u5b9a\u4e49\u4e860\u52309\u7b4910\u4e2a\u6570\u5b57\u3002\u5faa\u73af\u5224\u65ad\u4f60\u7ed9\u5b9a\u7684\u5b57\u7b26\u4e32\u91cc\u9762\u7684\u6bcf\u4e2a\u5b57\u7b26\uff0c\u5982\u679c\u53d1\u73b0\u5176\u4e2d\u4e00\u4e2a\u5b57\u7b26\u4e0d\u662f\u6570\u5b57\u5c31\u8fd4\u56de\u9519\u8bef\uff0c\u5982\u679c\u904d\u5386\u5b8c\u4e86\u90fd\u6ca1\u6709\u53d1\u73b0\u4e0d\u662f\u6570\u5b57\u7684\u5c31\u8fd4\u56de\u6b63\u786e

函数：startswith()作用，判断字符串是否以指定字符或子字符串开头。

s=input("please inupt string")
print(s.isdigit()) #用isdigit函数判断是否数字
print(s.isalpha()) #isalpha判断是否字母
print(not (s.isalpha() or s.isdigit()) and s.isalnum()) #isalnum判断是否数字和字母的组合

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