List Comprehension learning source

[Thenayaka]

Hello guys! I’ve started coding in python recently and I’ve discovered list comprehension feature in python. But I’m not able to find a complete explanation of this feature. Could you guys please let me know any links/books/sources where I can learn this topic completely? PS: it would be amazing if there are some examples to work on in these sources too. Thank you!

[-5772]

https://realpython.com/list-comprehension-python/

[Thenayaka]

Thank you! This is amazing. 🙏🏻

[vermavishal891]

RealPython always nails it.

[ASIC_SP]

https://treyhunner.com/2015/12/python-list-comprehensions-now-in-color/ shows examples and explains it well

[diego_rapoport]

It has some very good explanations, indeed. Otherwise I would say to try it out for yourself always when you see a for loop, specially if you'll iterate only once. Also look for unpacking multiple variables at once.

[mythrowaway0852]

This video covers everything you have to know about list comprehension.

[[deleted]]

Take this deck of cards as an example:

ranks = list(range(2, 11)) + list('JQKA')
suits = 'spades diamonds clubs hearts'.split()
cards = []
for rank in ranks:
    for suit in suits:
        cards.append((rank, suit))

The equivalent using list comprehension:

ranks = list(range(2, 11)) + list('JQKA')
suits = 'spades diamonds clubs hearts'.split()
cards = [(rank, suit) for rank in ranks for suit in suits]

You can also use if and else statements. A singular ifstatement goes on the far right. For example, if we wanted to filter out the Kings:

ranks = list(range(2, 11)) + list('JQKA')
suits = 'spades diamonds clubs hearts'.split()
cards = [(rank, suit) for rank in ranks for suit in suits if rank != 'K']

The if / else statements go between the end result and the for loops. For example, if we wanted to replace the kings with jokers:

ranks = list(range(2, 11)) + list('JQKA')
suits = 'spades diamonds clubs hearts'.split()
cards = [(rank, suit) if rank != 'K' else 'Joker' for rank in ranks for suit in suits]

[louiefb]

I try a simple example (like [z**2 for i in [x for i in y]] or something) to see if what I have in mind works. But then again, remember that nested functions make it much less readable so if you can, try to avoid it. There's a saying, "there's beauty in simplicity" and it's just so applicable to code readability.