Python：具有重复名称的字符串和不同整数的嵌套列表。 我怎样才能

Question

If I have the following nested list:

products.store = [['Shampoo', 35], ['Soap', 100], ['Soap', 150],['Towels', 45], ['Shampoo', 55]]

How can I write a program where each product is associated to total amount of products?

So that the output will still be in a nested list, like this: [['Shampoo', 90], ['Soap', 250],['Towels', 45]]

I have tried multiple solutions, but have failed to make the integers associated to a singular product.

Sorry if this is an easy question, it is my first term in university with coding. (Not for homework, a test or something like that). I would just love to learn how to improve my codes and better understand:) Thank you for your help!

Answer 1

Try:

products = [
    ["Shampoo", 35],
    ["Soap", 100],
    ["Soap", 150],
    ["Towels", 45],
    ["Shampoo", 55],
]

out = {}
for a, b in products:
    out[a] = out.get(a, 0) + b

out = list(map(list, out.items()))
print(out)

Prints:

[["Shampoo", 90], ["Soap", 250], ["Towels", 45]]