How to find the maximum of sublists in arbitrary nested list?
Question:
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]]]
Answers:
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]]]
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))
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]]]
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))
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]]]
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
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.
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]]]
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]]]
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]]]
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))
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]]]
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))
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]]]
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
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.
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]]]