How to group the values of list elements into other lists with Python

In this article, I'll be showing you how to implement a python algorithm that pushes the values of list items into another list.

I'd also be showing how to apply this algorithm in solving real-world problems.

First, let's assume you have a blog that publishes sport news. And you want to implement a functionality that tells your blog readers the teams that won and lost matches during the week.

Let's say your data structure is in this form:

#home team name, away team name, result
Matches = [
    ['Chelsea', 'Brighton', 'home team win'],
    ['Burnley', 'Arsenal', 'away team win'],
    ['Man city', 'Sheffield', 'home team win']
]

And you want the result to be like this:

team_win = ['Chelsea', 'Arsenal', 'Man city']
team_lost = ['Brighton', 'Burnley', 'Sheffield']

This is how you implement it in python:

First, create 3 variables: matches, team_win, team_lost.

#home `team name`, `away team name`, `result`
matches = [
    ['Chelsea', 'Brighton', 'home team win'],
    ['Burnley', 'Arsenal', 'away team win'],
    ['Man city', 'Sheffield', 'home team win']
]
team_win = []
team_lost = []

Next, you'll you a for loop to iterate over the values of matches variable.

for i in matches:

Within the loop, If the third item (result) of the list element is 'home team win', append the first item(home team name) of the list element to team_win variable. Else, append it to the team_lost variable

for i in matches:
    if i[2] == 'home team win':
        team_win.append(i [0])
    else:
        team_lost.append(i [0])

If the third item (result) of the list element is 'away team win', append the second item(away team name) of the list element to team_win variable. Else, append it to the team_lost variable

for i in matches:
    #...
    if i[2] == 'away team win':
        team_win.append(i [1])
    else:
        team_lost.append(i [1])

At the end, this is how your code should be look like:

#home team name, away team name, result
matches = [
    ['Chelsea', 'Brighton', 'home team win'],
    ['Burnley', 'Arsenal', 'away team win'],
    ['Man city', 'Sheffield', 'home team win']
]
team_win = []
team_lost = []

for i in matches:
    if i[2] == 'home team win':
      team_win.append(i[0])
    else:
      team_lost.append(i [0])

    if i[2] == 'away team win':
      team_win.append(i[1])
    else:
      team_lost.append(i [1])

print(team_win)
#['Chelsea', 'Arsenal', 'Man city']
print(team_lost)
#['Brighton', 'Burnley','Sheffield']

You can try implementing this algorithm for the following scenarios:
1) separate male and female products from a list containing product information

2) separate months where the sales is greater than 100,000 from those whose sales is lesser than 100,000

3) separate debtors from creditors

I hope you've understood how to implement this algorithm. Cheers.