Python - convert list of lists into matrix

Question

I am using python, I have a list which contains inside it group of lists how can I convert it into one matrix?

for example,

Root_List = [list1  list2  list3]
list1 = [1 2 3]
list2 = [1 5 9]
list3 = [2 4 1]

I need matrix to have below value

Any idea? Thank you in advanced.

Question has nothing to do with `keras` - kindly do not spam the tag (removed). — desertnaut, Nov 22 '18 at 00:07

score 2 · Answer 1 · answered Nov 21 '18 at 08:43

2

If they all have the same length, try this:

import numpy as np
list1 = [1,2,3]
list2 = [1,5,9]
list3 = [2,4,1]
Root_List = [list1, list2,list3]
np.array(Root_List)

answered Nov 21 '18 at 08:43

Manrique

hayj · Answer 2 · 2018-11-21T08:50:20.733

A matrix is a list of list.

Best practice is to first define your root list, then append sublists you want:

Root_List = []
list1 = [1, 2, 3]
Root_List.append(list1)
list2 = [1, 5, 9]
Root_List.append(list2)
list3 = [2, 4, 1]
Root_List.append(list3)

As suggested by @Antonio Manrique, you can also convert it using numpy to benefit matrix calculation functions of this lib. This answer answer how to convert a python list of list to a numpy matrix.

2 Answers2