Python check if list items are integers? [duplicate]

Question

I have a list which contains numbers and letters in string format.

mylist=['1','orange','2','3','4','apple'] 

I need to come up with a new list which only contains numbers:

mynewlist=['1','2','3','4'] 

If I have a way to check if each item in list can be converted to Integer, I should be able to come up with what I want by doing something like this:

for item in mylist:     if (check item can be converted to integer):         mynewlist.append(item) 

How do I check that a string can be converted to an integer? Or is there any better way to do it?

Answer 1

Try this:

mynewlist = [s for s in mylist if s.isdigit()] 

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From the docs:

str.isdigit()

Return true if all characters in the string are digits and there is at least one character, false otherwise.

For 8-bit strings, this method is locale-dependent.

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As noted in the comments, isdigit() returning True does not necessarily indicate that the string can be parsed as an int via the int() function, and it returning False does not necessarily indicate that it cannot be. Nevertheless, the approach above should work in your case.