Turning a list into nested lists in python

This groups each 3 elements in the order they appear:

new_list = [data_list[i:i+3] for i in range(0, len(data_list), 3)]

Give us a better example if it is not what you want.

Something like:

map (lambda x: data_list[3*x:(x+1)*3], range (3))

This assumes that data_list has a length that is a multiple of three

i=0
new_list=[]
while i<len(data_list):
  new_list.append(data_list[i:i+3])
  i+=3

Based on the answer from Fred Foo, if you're already using numpy, you may use reshape to get a 2d array without copying the data:

import numpy
new_list = numpy.array(data_list).reshape(-1, 3)

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