006 如何检测一个字符串是否可以转换为数字

检测字符串是否为数字

s1 = '123456'
s2 = '12.45'
s3 = 'ab12'
s4 = 'abc'
s5 = 'ab_12'
print(s1.isdigit())
print(s1.isdecimal())
print(s1.isnumeric())
print(s2.isdigit())
print(s2.isdecimal())
print(s2.isnumeric())
print(s3.isalnum())
print(s4.isalpha())
print(s5.isalnum())

True
True
True
False
False
False
True
True
False

 

如果将字符串转换为整数，如何做才安全

s1 = '1234a'
if s1.isdigit():
    print(int(s1))
else:
    print(s1, '不是数字，无法转换')

try:
    print(int(s1))
except Exception as e:
    print(e)


1234a 不是数字，无法转换
invalid literal for int() with base 10: '1234a'