How to remove all strings from a list of tuples python

Question

I am trying to remove all strings from a list of tuples

ListTuples = [(100, 'AAA'), (80, 'BBB'), (20, 'CCC'), (40, 'DDD'), (40, 'EEE')]

I have started to try and find a solution:

output = [i for i in ListTuples if i[0] == str]

print(output)

But I can't seem to get my head around how I would get an output like:

[(100), (80), (20), (40), (40)]

The format is always (int, str).

Answer 1

Use a nested tuple comprehension and isinstance:

output = [tuple(j for j in i if not isinstance(j, str)) for i in ListTuples]

Output:

[(100,), (80,), (20,), (40,), (40,)]

Note that there are trailing commas in the tuples to distinguish them from e.g. (100) which is identical to 100.

Answer 2

Since extracting the first item of each tuple is sufficient, you can unpack and use a list comprehension. For a list of tuples:

res = [(value,) for value, _ in ListTuples]  # [(100,), (80,), (20,), (40,), (40,)]

If you need just a list of integers:

res = [value for value, _ in ListTuples]     # [100, 80, 20, 40, 40]

For a functional alternative to the latter, you can use operator.itemgetter:

from operator import itemgetter
res = list(map(itemgetter(0), ListTuples))   # [100, 80, 20, 40, 40]

Answer 3

Here's another solution using filter():

def non_string(x):
    return not isinstance(x, str)

print([tuple(filter(non_string, x)) for x in ListTuples])
# [(100,), (80,), (20,), (40,), (40,)]