I am an absolute beginner in python so please guide me where wrong. I have a nested list of scores for which I need to calculate the sum of all positive integers and the [-1] index. I have converted the nested loop into flatlist and now tried the sum but I seem to be getting the total as 0. Answer should be 3150.

Can you please tell me where I am wrong?

#Create a 2D matrix with scores

#matrix (Column, Row) is a list of lists

matrix = [[0,-1000,0,0,0], [0,0,150,0,-1000], [0,-1000,1000,-1000,0], [-1000,1000,-1000,-150,0], [1000,150,0,0,-150]]

#convert nested list into flatlist

matrix_flatList = [ item for elem in matrix for item in elem]
print(matrix_flatList) 

def dream_score(matrix_flatlist):
    """
    A function that returns the max possible score 
    """
total = 0

#Iterate each positive element in list and add them in variable total

n = len(matrix_flatList)
for i in range(0,n): 
    if i > 0 and i == -150:
        total == total   matrix_flatList[i]
   
#printing dream score

print("Dream score is: ", total)
            
    
#make sure to get the last variable in total even if its negative

#return final score

CodePudding user response：

You have to change your for loop to get the exact output.

for i in matrix_flatList:
    if i > 0 and i == 150:
        total  = i

But, what do you mean by i == -150 exactly?

CodePudding user response：

The problem happens in

if i > 0 and i == -150:

i can not be a positive value and -150 at the same time.

Maybe you want to use or instead.

Also if you want to find the element with index -1, it would be better to use the list indexing instead of using -150 explicitly.