无法将 map() 的结果分配给二维列表

Question

下面的代码是在数组中取出一组学生分数行，需要找到分数最高的行。
下面是不完整的代码，因为仍然需要搜索最大总和行；但由于错误而停留在不完整的代码上。

它在 py3.codeskulptor.org/, while in Pythontutor 中给出了以下错误，程序在相同的行号处终止。

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])

还请提出一个更清晰的方法来解决上述问题。

P.S. 我发现上面的代码几乎是错误的，但把我踢到了正确的方向。
将下面的修改代码与调试过程中出现的问题有关：

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

max() 的这种行为是在将第 13 行错误地表述为：

时检测到的

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

正确的工作代码如下，输出 :

# 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)

请求 max() 显示的优先级的原因，如果可能的话 link 参考 CPython 中的底层实现的答案。

Answer 1

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

考虑到 arr 的上述构造，您在嵌套循环中交换了 t 和 n：

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

进入arr的第一个索引（对应于outer循环）必须是0到n之间的数字– 1.

进入arr的第二个索引（对应于内部循环）必须是0到t之间的数字– 1.

Answer 2

你把 t 和 n 搞错了

我应该在 range(n)

j 应该在 range(t)

无法将 map() 的结果分配给二维列表

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

cpython

python-3.x

python-internals