Python - List Comprehensions

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List Comprehensions



List comprehensions are a useful way of quickly creating lists whose contents obey a simple rule.
For example, we can do the following:
# a list comprehension
cubes = [i**3 for i in range(5)]

print(cubes)
Result:>>>
[0, 1, 8, 27, 64]
>>>
List comprehensions are inspired by set-builder notation in mathematics.


A list comprehension can also contain an if statement to enforce a condition on values in the list.
Example:
evens=[i**2 for i in range(10) if i**2 % 2 == 0]

print(evens)

Trying to create a list in a very extensive range will result in a MemoryError.
This code shows an example where the list comprehension runs out of memory.
even = [2*i for i in range(10**100)]
Result:>>>
MemoryError
>>>
This issue is solved by generators, which are covered in the next module.




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