3 follow-up notes on 3 python list comprehension tricks

I saw the following post about list comprehension tricks in Python. I really like python comprehension functionality – dict, set, list, I don’t discriminate. So 3 follow up notes about this post –

1. Set Comprehension

Beside dictionary and lists, comprehensions also work for sets –

{s for s in [1, 2, 1, 0]}
{s**2 for s in [1,2,1,0,-1]}

2. Filtering (and a glimpse to generators)

In order to filter a list, one can iterate over the list or generator, apply the filter function and output a list or can use the build-in filter function and receive a generator that is more efficient as described further in the original post.

words = ['deified', 'radar', 'guns']
palindromes = filter(lambda w: w==w[::-1], words)
#['deified', 'radar']

Additional nice to know the build-in function is the map function, that for example can yield the words’ lengths as generators – 

words = ['deified', 'radar', 'guns']
lengths = map(lambda w: len(w), words)
#[7, 5, 4]

3. Generators

Another nice usage of generators is to create an infinite sequence – 

def infinite_sequence():


    while True:

        yield num


gen = infinite_sequence()







Generators can be piped, return multiple outputs, and more. I recommend this postto a better understand generators.


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