Python - split a list in to smaller lists

So, you end up with a big list, that has a lot of entries, and you want to split them in to smaller lists.

My niece called me recently. She is doing her MA in Neuropsychology and has a set of readings from her research, where she wants to get a median for every minute. That means, she wants to split all her readings into smaller list, containing 60 entries.

Assuming that I’ve already split all her ~800,000 entries into a big list with:

import csv
import statistics 

datalist = []
with open(filename, 'r', encoding='utf-8-sig') as csvfile:
    datareader = csv.reader(csvfile)
for row in datareader:
        datalist.append(float(row[0]))

MAX_SIZE = 60

Then, I found via google this one liner, which is great.

composite_list = [datalist[x:x+MAX_SIZE] for x in range(0, len(datalist),MAX_SIZE)]

This is a great little one liner. It is a List Comprehension, that creates a list using a slice.

It will return a list of lists, which is my situation, is great.

Kabads