Most efficient way to remove non-numeric list entries

Question

I'm looking to 'clean' a list by excluding any items which contain characters other than 0-9, and wondering if there's a more efficient way than e.g.

import re
invalid = re.compile('[^0-9]')    
ls = ['1a', 'b3', '1']
cleaned = [i for i in ls if not invalid.search(i)]
print cleaned
>> ['1']

As I'm going to be operating on large-ish lists (5k items) of long strings (15 chars).

Answer 1

You can use isnumeric function. It checks whether the string consists of only numeric characters. This method is present only on unicode objects. It won't work with integer or float values

myList = ['text', 'another text', '1', '2.980', '3']
output = [ a for a in myList if a.isnumeric() ]
print( output )      
# Output is : ['1', '3']

Ref: https://www.tutorialspoint.com/python/string_isnumeric.htm

Answer 2

Anything wrong with the string method isdigit ?

>>> ls = ['1a', 'b3', '1']
>>> cleaned = [ x for x in ls if x.isdigit() ]
>>> cleaned
['1']
>>>