python中的正则表达式，用于检查字符串是否仅包含字母，数字和点（。）

Question

I am trying to develop a regular expression for match if a string just contains letters, numbers, space and dot(.) anywhere and with no order.

Like this:

hello223 3423.  ---> True
lalala.32 --->True
.hellohow1 ---> True
0you and me = ---> False (it contains =)
@newye ---> False (it contains @)
With, the name of the s0ng .---> False (it start with ,)

I am trying with this one but is always returning match:

m = re.match(r'[a-zA-Z0-9,. ]+', word)

Any idea?

Other way to formulate the question is are there any character diferent of letters, numbers, dot and space?

Thanks in advance

Answer 1

您需要添加$ ：

re.match(r'[a-zA-Z0-9,. ]+$', word)

Answer 2

re.search() solution:

import re

def contains(s):
    return not re.search(r'[^a-zA-Z0-9. ]', s)

print(contains('hello223 3423.'))    # True
print(contains('0you and me = '))    # False
print(contains('.hellohow1'))        # True