如何检查字符串是否包含字母？

Question

I have a numerical string which sometimes it contains letters. I must delete letters and everything after that from my input string. I have tried:

import re
b = re.split('[a-z]|[A-Z]', a)
b = b[0]

But this returns error whenever the string doesn't contain letters.

Do I need to check if a contains letters before trying to split at their point?

How can I check that ?

Two examples:

a = '1234' 

and

a = '1234h'

I want to have b = '1234' after both

---

Another example:
I want a= '4/200, 3500/ 500 h3m' or a= '4/200, 3500/ 500h3m' to return something like:

b= ['4', '200', '3500', '500']

Answer 1

import re
match = re.search('^[\d]+', '1234h')
if match:
    print(match.group(0))

It will return '1234' for '1234' and '1234h'. It find series of digits after starting and ignores after letter.

Answer 2

list = ['1234abc' , '5278', 'abc58586']

def range_sanitizer(s, lower_bound, upper_bound):
    return ''.join([x for x in s if lower_bound < x < upper_bound])

def remove_non_digits(s):
    return range_sanitizer(s, '0', '9')

def sanitize_list(list, sanitizer=remove_non_digits):
    return [sanitizer(item) for item in list]

if '__main__' == __name__:
    sanitized_list=sanitize_list(list)

    # ['1234', '5278', '58586']
    print(sanitized_list)