Question

Is it possible to basically do the following in Python:

for elem in my_list if elem:
    #Do something with elem...

Note that I want to specifically avoid using map, lambdas, or filter to create a second list that gives the Boolean condition, and I don’t want to do the following:

for elem in [item for item in my_list if item]:
    #Do something...

The latter method requires the construction of the Boolean list too. In my code, my_list can be very, very large.

Basically, the simplest way would be to write

for elem in my_list:
    if elem:
        #Do stuff...

but I specifically want this all in one line. If all-in-one-line won’t make the code actually any different than this last example I gave, that’s fine too and I will go with that.

Answer 1

You can use a generator expression instead of a list comprehension.

for elem in (item for item in my_list if not (item=='')):
    #Do something...