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pythonlistlist-comprehension

List comprehension to get second and fourth element

Suppose I have a list of lists:

mylist = [
    [2.1, 5.2, 6.1, -0.1],
    [2.2, 4.8, 5.6, -1.0],
    [3.3, 6.5, 5.9, 1.2],
    [2.9, 5.6, 6.0, 0.0],
]

How do I get the second [1] and fourth [3] element using a list comprehension to get a new list? It should look like this:

result =[
[5.2, -0.1],
[4.8, -1.0],
[6.5, 1.2],
[5.6, 0.0]
]
Solution

  • You can do this,

    result = [[item[1],item[3]] for item in mylist]
print(result)
# [[5.2, -0.1], [4.8, -1.0], [6.5, 1.2], [5.6, 0.0]]

    Just access the 1 and 3 elements and put them into another list.