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If I had two strings, 'abc' and 'def', I could get all combinations of them using two for loops:
for j in s1: for k in s2: print(j, k) However, I would like to be able to do this using list comprehension. I've tried many ways, but have never managed to get it. Does anyone know how to do this?
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Example List comprehension nested for loop. Simple example code uses two for loops in list Comprehension and the final result would be a list of lists. we will not include the same numbers in each list. we will filter them using an if condition.
List Comprehensions are one of the most amazing features of Python. It is a smart and concise way of creating lists by iterating over an iterable object. Nested List Comprehensions are nothing but a list comprehension within another list comprehension which is quite similar to nested for loops.
lst = [j + k for j in s1 for k in s2] or
lst = [(j, k) for j in s1 for k in s2] if you want tuples.
Like in the question, for j... is the outer loop, for k... is the inner loop.
Essentially, you can have as many independent 'for x in y' clauses as you want in a list comprehension just by sticking one after the other.
To make it more readable, use multiple lines:
lst = [ j + k # result for j in s1 # for loop for k in s2 # for loop # condition ] Since this is essentially a Cartesian product, you can also use itertools.product. I think it's clearer, especially when you have more input iterables.
itertools.product('abc', 'def', 'ghi') If you love us? You can donate to us via Paypal or buy me a coffee so we can maintain and grow! Thank you!
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