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pythonmultidimensional-arraymultiplication

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):    
    newAd = juv * list[0]
    return newAd

def funcTwo(ad,sen):
    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.


Solution

  • 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):    
        newAd = juv * list[0]
        return newAd
    
    def funcTwo(ad,sen):
        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):    
        newAd = juv * list[0][0]
        return newAd
    
    def funcTwo(ad,sen):
        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.