How can I get around declaring an unused variable in a for loop?

python list-comprehension
Ramy picture Ramy · Mar 29, 2011 · Viewed 32.6k times · Source

If I have a list comprehension (for example) like this:

['' for x in myList]

Effectively making a new list that has an empty string for every element in a list, I never use the x. Is there a cleaner way of writing this so I don't have to declare the unused x variable?

Answer

kennytm picture kennytm · Mar 29, 2011

_ is a standard placeholder name for ignored members in a for-loop and tuple assignment, e.g.

['' for _ in myList]

[a+d for a, _, _, d, _ in fiveTuples]

BTW your list could be written without list comprehension (assuming you want to make a list of immutable members like strings, integers etc.).

[''] * len(myList)

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