How to write an if condition such that python should execute if statement if the element in a listcan be converted to type int

Question

How can i write the code for an if condition where i want to see if i can convert the type of an element in a list to int. If its possible, then if condition should be executed.Otherwise, it should go to else statement

For eg:

lst=['@','#','^','%','20']

''' Now i am going to iterate through the list and check if i can convert the elements  to type int. If it can be converted then i know there is a number in the list and i do some operations on the number'''

for ele in lst:
    if(type(int(ele)=='int'):
        #do some operation on the number eg:20/2 and print the value
    else:
        continue

Please give me an idea as to how to write the if condition.

You should instead `try` to convert the element to int and proceed if successful, `except` that you do something else when that fails with a `ValueError`. — Karl Knechtel, Nov 15 '20 at 17:09
Does this answer your question? [Python: Test if value can be converted to an int in a list comprehension](https://stackoverflow.com/questions/5606585/python-test-if-value-can-be-converted-to-an-int-in-a-list-comprehension) — Mickey, Nov 15 '20 at 17:14

score 1 · Answer 1 · answered Nov 15 '20 at 17:19

1

Try to convert to int and catch the error:

for ele in lst:
    try:
        val = int(ele)
    except ValueError:
        continue
    else:
        print(val)

answered Nov 15 '20 at 17:19

Christian K.

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score 0 · Answer 2 · answered Nov 15 '20 at 17:09

0

Try with .isdigit()+a list comprehension (perfect couple ;-):

lst=['@','#','^','%','20']
[str(x).isdigit() for x in lst]

Caveat: does not work for float strings, for floats:

[str(x).replace('.','').isdigit() for x in lst]

answered Nov 15 '20 at 17:09

Wasif

14,755
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Sash Sinha · Accepted Answer · 2020-11-15T17:33:01.637

0

You could check if each element is an int using a try block in a helper function is_int:

def is_int(s):
    try: 
        int(s)
        return True
    except ValueError:
        return False

lst = ['@', '#', '^', '%', '20']
for s in lst:
    if is_int(s):
        int_s = int(s)
        print(f'{int_s}/2 = {int_s/2}')
    else:
        continue

Output:

20/2 = 10.0

edited Nov 15 '20 at 17:33

answered Nov 15 '20 at 17:15

Sash Sinha

18,743
3
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score 0 · Answer 4 · answered Nov 15 '20 at 17:26

0

I think what you are looking for is :

if isinstance(ele,int)

lst = ['@', '#', '^', '%', 20]

for ele in lst:
    if isinstance(ele,int):
        print("This is int: " + str(ele))
    else:
        print("This is not int: " + ele)

Very simple and easy.

answered Nov 15 '20 at 17:26

IceJonas

720
6
13

Thank you. But I am checking if the elements can be converted to int type. not if the element is of type int. – loginator Nov 15 '20 at 17:38
Oh sorry about that :) – IceJonas Nov 15 '20 at 17:45

How to write an if condition such that python should execute if statement if the element in a listcan be converted to type int

4 Answers4