how to iterate the list

Question

I want to iterate the list over 500+ times.

right now I am using by single method:

col1,col2,col3,col4,col5,col6,col7,col8,col9,col10 = [],[],[],[],[],[],[],[],[],[] 

     for x in range [3,500]:
        col+str(x) = []

the "col" should be constant and iteration should be over 500 times

it's really not necessary to create 497 `col` variables. Use a different data structure :) — David Zemens, Jul 30 '19 at 14:53
use dict or list comprehension: `columns = {i:[] for i in range(3,500)}` or `columns = [[] for i in range(3,500)]`. — David Zemens, Jul 30 '19 at 14:57
If you really need to do this (which you shouldn't), you can do for x in range(500): exec("col" + str(x) + "=[]") — mattsap, Jul 30 '19 at 14:58
thank you for the help, but unfortunately again stuck in looping :( — Ron Ledger, Jul 30 '19 at 15:48

score 4 · Answer 1 · answered Jul 30 '19 at 14:53

4

just use a list (of lists):

cols = []
for x in range(500):
    cols.append([])

then you can access each individual col by cols[42] (or any other index...)

answered Jul 30 '19 at 14:53

Adam.Er8

Do it in one line: cols = [[] for x in range(500)] – mattsap Jul 30 '19 at 14:55
You can just do `cols = [[]]*500`. – Acccumulation Jul 30 '19 at 16:18
@Acccumulation no no, see this: https://ideone.com/YkZt89 – Adam.Er8 Jul 30 '19 at 16:26

1 Answers1