Iterating over lists within a list

Question

I have written some code to iterate over a list of lists that returns true or false based on if i at an index in a list is bigger than all other values j at the same index in other lists:

for i in range(len(list)):
    for j in range(0, len(list)):
        if (np.any(list[i]) >= np.all(list[j])):
            count = count + 1
            results.append((count == len(list) - 1))

print (results)

this works fine in finding the right answer. However, the problem is that the function doesn't iterate over the entirety of the list inside the list like I would hope. For example, from a list like this:

list =[[1, 3, 6, 5, 9], [7, 2, 8, 9, 1]]

I would expect an output like this:

results = [False, True, True, False, False, True, False, True, True, False]

However, it is only iterating over the first two indices and stops.

results = [False, True, True, False]

I know this is probably because the length of list is 2, but I don't have a good solution for getting the function to iterate over the entire list inside the list. Any help would be greatly appreciated!

Answer 1

Try to avoid using Python keywords as variable names (eg: list ). But if you calculate the maximum value per column before looping, you can then more easily calculate what you after like this:

Code:

lst = [[1, 3, 6, 5, 9], [7, 2, 8, 9, 1]]
maxes = [max(x) for x in zip(*lst)]
print([r == m for row in lst for r, m in zip(row, maxes)]

Or as a standard for loop:

result = []
for row in lst:
    for r, m in zip(row, maxes):
        result.append(r == m)

Results:

[False, True, False, False, True, True, False, True, True, False]