Facing some complication in my for loop statement?

Question

I am using python 3.

for i in range(len(basic_elements)):
    value_list = [basic_elements[i], x_count[i]]

basic_element is a list of words, and x_count is a list of number. I want value_list to give me all the 50 elements in both lists together in value_list. But i kept on getting only the last element. I don't understand?!

Then you need to build a list with `.append`. Here you are just replacing `value_list` with a new, two-element list each time. — juanpa.arrivillaga, Mar 20 '17 at 19:57
But basically, this can be achieved using `value_list = list(zip(basic_elements, x_count))` — juanpa.arrivillaga, Mar 20 '17 at 19:58
use zip to merge the two list http://stackoverflow.com/questions/1663807/how-can-i-iterate-through-two-lists-in-parallel-in-python — Rob, Mar 20 '17 at 19:58

zyd · Accepted Answer · 2017-03-20T20:08:52.053

0

Doing the list assigment inside the loop re-initializes the list each time the loop is executed. I'm not entirely sure what you want your output list to look like, but something long the lines of

values_list = []
for i in range(len(basic_elements)):
    value_list.append((basic_elements[i], x_count[i]))

should create a list of basic_elements[i], x_count[i] tuples.

edited Mar 20 '17 at 20:08

answered Mar 20 '17 at 20:01

zyd

833
7
16

There's no list comprehension in his code. – Barmar Mar 20 '17 at 20:01
...[basic_elements[i], x_count[i]] is a list comprehension – zyd Mar 20 '17 at 20:04
or looks like an attempt at one anyway – zyd Mar 20 '17 at 20:06
I thought a list comprehension is something like `[x**2 for x in other_list]` – Barmar Mar 20 '17 at 20:07
`[[basic_elements[i], x_count[i]]` is simply a list literal. – Barmar Mar 20 '17 at 20:07
my bad, I stand corrected I was thinking too deep, you're just assigning a new list every loop over your old list. – zyd Mar 20 '17 at 20:08
Thank you very much, it helped!!! – Sam H Mar 20 '17 at 20:53

Facing some complication in my for loop statement?

1 Answers1