Is there a built-in function that pulls a column from the nested list?

If there is an overlapping list such as lst in the code below, take out the column you want and make it a list Is there a built-in function?

Is there a embedded function that runs the second for loop part as one function and stores it in col_2 below?

lst = []
for i in range(5):
    dicTest = { 0: 0, 1: 0, 2: 0}
    dicTest[i%3] += 1
    lst.append([[i]*3,dicTest,i*2,i*3])
    print(lst[i])

col_2 = []
for i in range(5):
    col_2.append(lst[i][2])
print(col_2)

Execution result

[[0, 0, 0], {0: 1, 1: 0, 2: 0}, 0, 0]
[[1, 1, 1], {0: 0, 1: 1, 2: 0}, 2, 3]
[[2, 2, 2], {0: 0, 1: 0, 2: 1}, 4, 6]
[[3, 3, 3], {0: 1, 1: 0, 2: 0}, 6, 9]
[[4, 4, 4], {0: 0, 1: 1, 2: 0}, 8, 12]
[0, 2, 4, 6, 8]

python list

2022-09-21 18:43

1 Answers

There is no such built-in function in the Python default list, instead

col_2 = [i[2] for i in lst]

You can abbreviate to .

The built-in function you want is implemented in the numpy module array type. For example, if you are running the following code:

import numpy

lst = numpy.array([ [1,2,3], [4,5,6], [7,8,9] ])

print lst[:,2]

Here's the result

`` [3 6 9]

2022-09-21 18:43

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