How to duplicate list elements according to another counts list?

Question

I have two lists and I'm trying to create multiple copies of numbers based on how many times they occur.

numbers = [0, 1, 2]
amount = [1, 2, 3]

I tried:

total = []
n = 0
for i in range(len(numbers)):
    product = numbers[n] * amount[n]
    n += 1
    total.extend(product)

But I got the error:

TypeError: 'int' object is not iterable.

My expected output is:

total = [0, 1, 1, 2, 2, 2]

Change ```total.extend(product)``` to ```total.append(product)``` That will fix your type error, but the code is flawed in the logic, so you won't get the expected result. — Rashid 'Lee' Ibrahim, Aug 26 '20 at 16:06
Why are you maintaining `n` when you can just use `i` - the loop's variable? — Tomerikoo, Aug 26 '20 at 16:12
@Rashid'Lee'Ibrahim your suggested fix will make the code have flawed logic... OP's code simply has two brackets missing to make it work as expected, I wouldn't say his logic is flawed — Tomerikoo, Aug 26 '20 at 16:18

sushanth · Answer 1 · 2020-08-26T16:13:04.913

3

result = []
for i, j in zip(numbers, amount):
    result.extend([i] * j)

print(result)

[0, 1, 1, 2, 2, 2]

edited Aug 26 '20 at 16:13

answered Aug 26 '20 at 16:07

sushanth

score 2 · Answer 2 · answered Aug 26 '20 at 16:06

Your error is within the line:

product = numbers[n] * amount[n]

it doesnt result in a list but an integer. Since you're multiplying two numbers.

What you actually want is

product = [numbers[n]] * amount[n]

2 Answers2