Unable to assign result of map() to 2-D list

Question

The below code is for taking a set of rows of students' marks in array, and need find the row with maximum marks.
Below is incomplete code, as need to search for the maximum sum row still; but stuck at the incomplete code due to error.

It gives below error in py3.codeskulptor.org/, while in Pythontutor, the program terminates at the same line number.

Line #17: IndexError: list assignment index out of range

# Input number of tests 
t = int(input("Input number of tests")) 

# Input size of rows (of students) 
n = int(input("Input size of rows"))#.strip().split()) 
print (t,n)

arr = [[[] for i in range(t)] for i in range(n)] 
total = [[] for i in range (n)]  

for i in range(0,t): 

    # Input score of each student in row     
    sum =0    
    for j in range(n):
        arr[i][j] = map(int, input("Input score").strip().split())#[:n]
    #the above line causes compilation error

    # Find sum of all scores row-wise 
    for m in arr[i][j]:
        sum += m
    total[i] = sum1

# Find the max. of total
for j in range(t): 
    y = max(total[j])

Please also suggest a crisper approach to program the above problem.

P.S. I found the above code to be nearly wrong, but kicked me in correct direction.
Have the modified code below with a question that arose during debugging that concerns the :

max() giving precedence to [] over an integer value

This behaviour of max() was detected when incorrectly stated line #13 as :

total = [[[] for i in range (l)] for i in range (n)]

The correct working code is below, with output :

# Input number of tests 
t = int(input("Input number of tests")) 

# Input number of rows (of students) 
n = int(input("Input number of rows"))#.strip().split()) 

# Input limit on number of students in a row (of students) 
l = int(input("Input max. number of studentsin any row"))#.strip().split()) 

print ('t :',t,'n :',n, 'l :', l)

arr = [[[[] for i in range(l)] for i in range(n)] for i in range(t)]
total = [[[] for i in range (n)] for i in range (t)]  

# run input of tests 
for i in range(t):   
    # Input score of each student in the i-th row, out of n   
    sum =0 
    for j in range(n):
        #for k in range(l):
        print("jkl:","i:",i,"j:",j)
        arr[i][j] = map(int, input("Input score").strip().split())[:l]


for i in range(t): 
    for j in range(n):
        # Find sum of all scores row-wise 
        sum = 0
        for m in arr[i][j]:
            #sum[i][j][] += m
            print ('m :', m)
            sum += m

        #total[i][j] = sum[i][j][]
        total[i][j] = sum

for i in range(t):
    print("Test no. ", i)
    for j in range(n):
        #for m in arr[i][j]:
        print (arr[i][j])
            #print (m)
    print("=========")

for i in range(t): 
    for j in range(n):
        print(i,"-",j, total[i][j])
    print("::::::")
print("=========")

# Find the max. of total
for i in range(t): 
     print([m for m in total[i]])
     y = max([m for m in total[i]])
     print ('i:',i,',', 'max total:',y)

Request reason for the precedence shown by max(), and if possible link the answer with some reference to underlying implementation in CPython.

Answer 1

arr = [[[] for i in range(t)] for i in range(n)] 

Considering the above construction of arr, you have swapped t and n in the nested loops:

for i in range(t):
    # …
    for j in range(n):
        arr[i][j] = …

The first index into arr (corresponding to the outer loop) must be a number between 0 and n–1.

The second index into arr (corresponding to the inner loop) must be a number between 0 and t–1.