ProMCKingz - 1 year ago 185
Python Question

# Python - Multiplying an element from 2D list

I would like to multiply one of the elements from the 2D list by an integer. However, once I execute the code I get the following: I was expecting the outcome to be just a tuple, rather than a list, and would like for it to be a tuple rather than a list.

``````[3, 3, 3]
[6, 6, 3, 3, 3, 3]
``````

This is my code:

``````list = [[0.5],[0.3],[0.1]]

def funcOne(juv):

newSen = (ad* list[1]) + (sen* list[2])
return newSen

print(funcOne(3))
print(funcTwo(2,4))
``````

My desired output for funcOne would be to have 3*0.5 = 1.5, where "0.5" is list[0]. I am unsure about how to edit my code in order to achieve this outcome.

Actually I'm still confused about your explanation for the expected output. I just run your code the output is below:

``````[0.5, 0.5, 0.5]
[0.3, 0.3, 0.1, 0.1, 0.1, 0.1]
``````

The reason that your function will return a list instead of multiplying one of the elements in the 2d matrix is that you use the index for the element in the 2d matrix in a wrong way. Here is your code:

``````list = [[0.5],[0.3],[0.1]]

def funcOne(juv):

newSen = (ad* list[1]) + (sen* list[2])
return newSen

print(funcOne(3))
print(funcTwo(2,4))
``````

In your code, when you use `juv * list[0]` in the function `funcOne`, it actually execute as `3 * [0.5]`, where `[0.5]` is the first element of the 2d matrix(list). You can run in the Python interpreter and find that the result of `3 * [0.5]` is `[0.5, 0.5, 0.5]`, which means it just replicate the elements in the list three times.

If you want to calculate like `[[0.5 * 3], [0.3], [0.1]]`, you should change a little bit of your code as following:

``````def funcOne(juv):

newSen = (ad* list[1][0]) + (sen* list[2][0])
return newSen
``````

----------update

If you want to return the list like `[[1.5], [0.3], [0.1]]`. Change the code to

``````def funcOne(juv):
list[0][0] = juv * list[0][0]
return list
``````

Hope it helps.

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