How to find the maximum of sublists in arbitrary nested list?-CodePudding

I have a list C11 containing many sublists. I want to find the maximum element of each sublist. I present the current and expected outputs.

C11 = [[[353.856161, 0.0, 0.0], [0.0, 0.0, 282.754301, 0.0]], [[0.0, 294.983702, 126.991664]]]

for i in range(0,len(C11)):
    C2 = max(C11[i])
print(C2)

The current output is

[[353.856161, 0.0, 0.0], [0.0, 294.983702, 126.991664]]

The expected output is:

[[[353.856161],[282.754301]], [[294.983702]]]

CodePudding user response：

In case the depth is completely arbitrary and you want to keep the same nesting structure in the output, here is a recursive function that keeps going in levels until reaching a "leaf" (list with values and not lists) and takes the maximums:

def get_max(l):
    res = []
    if isinstance(l[0], list):
        for sub in l:
            res.append(get_max(sub))
    else:
        res.append(max(l))
    return res

print(get_max([[[353.856161, 0.0, 0.0], [0.0, 0.0, 282.754301, 0.0]], [[0.0, 294.983702, 126.991664]]]))

Will give:

[[[353.856161], [282.754301]], [[294.983702]]]

CodePudding user response：

Use this function in case the nesting-depth of the list is variable.

C11=[[[353.856161, 0.0, 0.0], [0.0, 0.0, 282.754301, 0.0]], [[0.0, 294.983702, 126.991664]]]


def find_max(ls: list) -> list:
    # does the list contain only numbers?
    if all((isinstance(x, float) for x in ls)):
        # if  yes return simple max
        return [max(ls)]
    else:
        # apply the function one level deeper
        return [find_max(x) for x in ls]

print(find_max(C11))

CodePudding user response：

List Comprehension

Code:-

C11=[[[353.856161, 0.0, 0.0], [0.0, 0.0, 282.754301, 0.0]], [[0.0, 294.983702, 126.991664]]]

res=[[[max(sublist)] for sublist in lis] for lis in C11]

print(res)

Output:

[[[353.856161], [282.754301]], [[294.983702]]]

CodePudding user response：

Here is a quick recursive generalized approach. Should work with any level of varying nesting.

c11 = [[[353.856161, 0.0, 0.0], [0.0, 0.0, 282.754301, 0.0]], [[0.0, 294.983702, 126.991664]]]

result = []

def traverse(arr, result):
    if len(arr) > 0:
        if type(arr[0]) is list:
            # check if item inside list is another list
            for i in arr:
                result = traverse(i, result)
        else:
            # if its a list of number, get the max and add it to result
            result.append(max(arr))
    return result

print(traverse(c11, result))

CodePudding user response：

Using recursive is the best option. Recursive works for any length of list. Used a initial validation to check if list element is empty.

Code:

check=[[[353.856161, 0.0, 0.0], [0.0, 0.0, 282.754301, 0.0]], [[0.0, 294.983702, 126.991664]]]

def recursive_max(lst):
    if len(lst) == 0:
        return []
    if isinstance(lst[0], list):
        min_val = []
        for val in lst:
            min_val.append(recursive_max(val))
        return min_val
    else:
        return [max(lst)]

print(recursive_max(check))

Output:

[[[353.856161], [282.754301]], [[294.983702]]]

CodePudding user response：

C11 array is multi dimension array need put in nested loop

C11 = [[[353.856161, 0.0, 0.0], [0.0, 0.0, 282.754301, 0.0]], [[0.0, 294.983702, 126.991664]]]
for i in range(0, len(C11)):
    for j in range(0, len(C11[i])):
        C2 = max(C11[i][j])
        print(C2)

Output

CodePudding user response：

I have assumed that the depth of the list is random.

I have used a recursive approach to replace a last-level list with a list of its maximum value.

def recurse(l):
    for index in range(len(l)):
        if type(l[index]) == list:
            l[index] = recurse(l[index])
        else:
            l = [max(l)]
            return l
    return l

Example:

l = [[5,3,8], [1,2,4], [[[2,4],[11,12]],[5,9]]]
recurse(l)
print(l)

Output:

[[8], [4], [[[4], [12]], [9]]]

Your Example:

C11=[[[353.856161, 0.0, 0.0], [0.0, 0.0, 282.754301, 0.0]], [[0.0, 294.983702, 126.991664]]]
recurse(C11)
print(C11)

Output:

[[[353.856161], [282.754301]], [[294.983702]]]

Note: The function updates the list inplace so if you want to restore the list, use a copy of the old list.

CodePudding user response：

Code:

C11=[[[353.856161, 0.0, 0.0], [0.0, 0.0, 282.754301, 0.0]], [[0.0, 294.983702, 126.991664]]]
C2=[]
for i in range(0,len(C11)):
    C2.insert(i, [])
    for j in range(0,len(C11[i])):
        C2[i].insert(j, [])
        C2[i][j].insert(0, max(C11[i][j]))
print(C2)

Output:

[[[353.856161], [282.754301]], [[294.983702]]]