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).

Do you know that you are always going to have items of the form [(<int>, <str>), ...]? — Jack Moody
– Jack Moody, Commented Jan 16, 2019 at 14:06
If the format is always (int, str) the following could be a simple solution: output = [(i[0],) for i in ListTuples] — Mark
– Mark, Commented Jan 16, 2019 at 14:09

CristiFati · Accepted Answer · 2019-01-16 14:10:26Z

9

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.

edited Jan 16, 2019 at 14:10

CristiFati

41.6k9 gold badges68 silver badges115 bronze badges

answered Jan 16, 2019 at 14:06

meowgoesthedog

15.1k4 gold badges30 silver badges43 bronze badges

Sign up to request clarification or add additional context in comments.

7 Comments

jpp Over a year ago

This answer does no match OP's desired output!

jpp Over a year ago

@RoadRunner, Not true, [(100), (80), (20), (40), (40)] is valid Python, it's a list of integers!

a.rowland Over a year ago

Thank you, this worked perfectly! I just have to change the isinstance(j, str) to isinstance(j, int) to get the integer values I'm after. I will accept this answer

tobias_k Over a year ago

I think this does match OP's desired output, or rather what OP (probably) intended to show, not how that's interpreted by Python.

tobias_k Over a year ago

@a.rowland If you want to "remove all strings", then you should use not isinstance(j, str), otherwise it would be "keep all integers", which is not strictly the same. (In your example, both would be equivalent, though.)

|

jpp · Accepted Answer · 2019-01-16 14:20:27Z

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]

edited Jan 16, 2019 at 14:20

answered Jan 16, 2019 at 14:13

jpp

166k37 gold badges301 silver badges363 bronze badges

Comments

RoadRunner · Accepted Answer · 2019-01-16 14:29:09Z

1

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,)]

edited Jan 16, 2019 at 14:29

answered Jan 16, 2019 at 14:23

RoadRunner

26.4k6 gold badges46 silver badges77 bronze badges

Comments

Henrique Zanferrari · Accepted Answer · 2019-01-16 14:27:38Z

0

Try this

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

ListInt = []
ListStr = []

for item in ListTuples:
    strAux = ''
    intAux = ''
    for i in range(0, len(item)):

        if(isinstance(item[i], str)):
            strAux+=item[i] 
        else:
            intAux+=str(item[i])


    ListStr.append(strAux)
    ListInt.append(intAux)


print(ListStr)

'''TO CONVERT THE STR LIST TO AN INT LIST'''
output= list(map(int, ListInt)) 
print(output)

The output is [100, 80, 20, 40, 40]

answered Jan 16, 2019 at 14:27

Henrique Zanferrari

1119 bronze badges

3 Comments

tobias_k Over a year ago

What are those "aux" accumulators for? Why not directly appen in the if/else? This will fail for [(1, "foo", 3)] or any other tuple that has more than one of each type, and for any other cases those "aux" variables have no use, either.

Henrique Zanferrari Over a year ago

If you appen in if/else it you retrieve 'A', 'A', 'A', 'B' 'B' and so on, because its inside for loop. If you try [(1, "foo", 3)]it will return 13 and foo

tobias_k Over a year ago

No, it does not, as you are not iterating the characters in the string, just the elements in the tuple. And, yes, it will return that, and I don't think that that's what OP intended.

cph_sto · Accepted Answer · 2019-01-16 15:39:38Z

0

We check if a particular value is a string or not using type(value).

output = [tuple([j for j in i if type(j)!=str]) for i in ListTuples]
print(output)
    [(100,), (80,), (20,), (40,), (40,)]

answered Jan 16, 2019 at 15:39

cph_sto

7,70714 gold badges49 silver badges91 bronze badges

Collectives™ on Stack Overflow

How to remove all strings from a list of tuples python

5 Answers 5

7 Comments

Comments

Comments

3 Comments

Comments

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

5 Answers 5

7 Comments

Comments

Comments

3 Comments

Comments

Your Answer

Sign up or log in

Post as a guest

Related