Compare two lists one to one in Python

Question

I am trying to compare each element of the two equal length lists.

import numpy as np

def comp_one2one(list1, list2):
    tmp = []
    for i in range(len(list1)):
        if list2[i] > list1[i]:
            tmp.append(True)
        else: 
            tmp.append(False)
    return np.any(tmp)
list1 = [10, 15, 20]
list2 = [50, 10, 15] 
> print(comp_one2one(list1,list2))
True

I am wondering if there is a more efficient and more pythonic way of doing this operation?

Yes, using [`zip`](https://docs.python.org/3.3/library/functions.html#zip) `any(l2 > l1 for l1, l2 in zip(list1, list2))` — Pranav Hosangadi, Oct 05 '20 at 21:34

aayushgupta · Answer 1 · 2020-10-05T21:37:53.620

1

def comp_one2one(list1, list2):    
    return all(np.array(list1)>np.array(list2))

edit: I missed the greater than, but you can change that to anything.

edited Oct 05 '20 at 21:37

answered Oct 05 '20 at 21:35

aayushgupta

64
5

@PranavHosangadi He has imported numpy, therefore I'm assuming that numpy will be used in part of the project so why not use it? – aayushgupta Oct 05 '20 at 21:38
Fair enough. You might as well use `np.all()` then. https://stackoverflow.com/a/43382396/843953 – Pranav Hosangadi Oct 05 '20 at 21:40

score 1 · Answer 2 · answered Oct 05 '20 at 21:38

1

Lik Pranav mentioned, you can zip the two lists together

list1 = [10, 15, 20]
list2 = [50, 10, 15] 
tmp = []
for l1,l2 in zip(list1,list2):
    if l2 > l1:
        tmp.append(True)
    else: 
        tmp.append(False)
        
tmp
#[True, False, False]

Or you can try list comprehension

[l2>l1 for l1,l2 in zip(list1,list2)]

#[True, False, False]

answered Oct 05 '20 at 21:38

willwrighteng

1,411
11
25

They return `np.any(tmp)` from the function, so you can also do `any(...)` without the brackets, because `any()` can take a generator expression. – Pranav Hosangadi Oct 05 '20 at 21:42
Sure that makes sense, thank you. My intention was to comment on the core algorithm. – willwrighteng Oct 05 '20 at 21:45

Compare two lists one to one in Python

2 Answers2