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How to make a Python function that operates on two or more nested lists of the same shape?
Convert two lists into a dictionaryHow can I safely create a nested directory?How do I return multiple values from a function?How can I make a time delay in Python?How to remove an element from a list by index?How to make a chain of function decorators?How to make a flat list out of list of listsHow do I get the number of elements in a list?How do I concatenate two lists in Python?How can I reverse a list in Python?
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I would like to apply an arbitrary function to two or more nested lists of the same shape. For instance if my function is:
def add(a, b):
if "NULL" not in [a, b]:
return a + b
else:
return "NULL"
and my inputs are:
input1 = [[1, 2, "NULL"], [3, 4], [5, 6, 7, 8]]
input2 = [[9, 8, "NULL"], [7, 6], [5, 4, 3, 2]]
Then I would like the output to be
output = [[10, 10, "NULL"], [10, 10], [10, 10, 10, 10]]
The inputs will always be nested one level deep, but the outputs ideally should be anything (for instance it could be nested deeper if the function was a "concatenate(a, b)" function)
python list
add a comment
|
I would like to apply an arbitrary function to two or more nested lists of the same shape. For instance if my function is:
def add(a, b):
if "NULL" not in [a, b]:
return a + b
else:
return "NULL"
and my inputs are:
input1 = [[1, 2, "NULL"], [3, 4], [5, 6, 7, 8]]
input2 = [[9, 8, "NULL"], [7, 6], [5, 4, 3, 2]]
Then I would like the output to be
output = [[10, 10, "NULL"], [10, 10], [10, 10, 10, 10]]
The inputs will always be nested one level deep, but the outputs ideally should be anything (for instance it could be nested deeper if the function was a "concatenate(a, b)" function)
python list
Will the lists only ever be nested one level deep?
– Peter Collingridge
Mar 28 at 21:08
@PeterCollingridge Yes, at least in the input stage (perhaps the output could be nested deeper depending on the function applied)
– AAC
Mar 28 at 21:24
If the lists are nested one level deep aways, why not[func(val) for val in list_of_lists]
or eventmap(func, list_of_lists)
, it would simplify your function.
– geckos
Mar 28 at 21:30
add a comment
|
I would like to apply an arbitrary function to two or more nested lists of the same shape. For instance if my function is:
def add(a, b):
if "NULL" not in [a, b]:
return a + b
else:
return "NULL"
and my inputs are:
input1 = [[1, 2, "NULL"], [3, 4], [5, 6, 7, 8]]
input2 = [[9, 8, "NULL"], [7, 6], [5, 4, 3, 2]]
Then I would like the output to be
output = [[10, 10, "NULL"], [10, 10], [10, 10, 10, 10]]
The inputs will always be nested one level deep, but the outputs ideally should be anything (for instance it could be nested deeper if the function was a "concatenate(a, b)" function)
python list
I would like to apply an arbitrary function to two or more nested lists of the same shape. For instance if my function is:
def add(a, b):
if "NULL" not in [a, b]:
return a + b
else:
return "NULL"
and my inputs are:
input1 = [[1, 2, "NULL"], [3, 4], [5, 6, 7, 8]]
input2 = [[9, 8, "NULL"], [7, 6], [5, 4, 3, 2]]
Then I would like the output to be
output = [[10, 10, "NULL"], [10, 10], [10, 10, 10, 10]]
The inputs will always be nested one level deep, but the outputs ideally should be anything (for instance it could be nested deeper if the function was a "concatenate(a, b)" function)
python list
python list
edited Mar 28 at 21:30
AAC
asked Mar 28 at 20:54
AACAAC
2161 silver badge9 bronze badges
2161 silver badge9 bronze badges
Will the lists only ever be nested one level deep?
– Peter Collingridge
Mar 28 at 21:08
@PeterCollingridge Yes, at least in the input stage (perhaps the output could be nested deeper depending on the function applied)
– AAC
Mar 28 at 21:24
If the lists are nested one level deep aways, why not[func(val) for val in list_of_lists]
or eventmap(func, list_of_lists)
, it would simplify your function.
– geckos
Mar 28 at 21:30
add a comment
|
Will the lists only ever be nested one level deep?
– Peter Collingridge
Mar 28 at 21:08
@PeterCollingridge Yes, at least in the input stage (perhaps the output could be nested deeper depending on the function applied)
– AAC
Mar 28 at 21:24
If the lists are nested one level deep aways, why not[func(val) for val in list_of_lists]
or eventmap(func, list_of_lists)
, it would simplify your function.
– geckos
Mar 28 at 21:30
Will the lists only ever be nested one level deep?
– Peter Collingridge
Mar 28 at 21:08
Will the lists only ever be nested one level deep?
– Peter Collingridge
Mar 28 at 21:08
@PeterCollingridge Yes, at least in the input stage (perhaps the output could be nested deeper depending on the function applied)
– AAC
Mar 28 at 21:24
@PeterCollingridge Yes, at least in the input stage (perhaps the output could be nested deeper depending on the function applied)
– AAC
Mar 28 at 21:24
If the lists are nested one level deep aways, why not
[func(val) for val in list_of_lists]
or event map(func, list_of_lists)
, it would simplify your function.– geckos
Mar 28 at 21:30
If the lists are nested one level deep aways, why not
[func(val) for val in list_of_lists]
or event map(func, list_of_lists)
, it would simplify your function.– geckos
Mar 28 at 21:30
add a comment
|
2 Answers
2
active
oldest
votes
How about:
def apply_f(a, b, f):
if isinstance(a, list):
return [apply_f(item_a, item_b, f) for item_a, item_b in zip(a, b)]
else:
return f(a, b)
result = apply_f(input1, input2, add)
add a comment
|
Assuming the lists are always the right length (you can put a check for this), make your function recursive:
def add(a, b):
if isinstance(a, list) and isinstance(b, list):
for a_sub, b_sub in zip(a, b):
return [add(a_sub, b_sub) for a_sub, b_sub in zip(a, b)]
elif "NULL" not in [a, b]:
return a + b
elif "NULL" in [a, b]:
return "NULL"
else:
raise ValueError("Wrong input shapes")
input1 = [[1, 2, "NULL"], [3, 4], [5, 6, 7, 8]]
input2 = [[9, 8, "NULL"], [7, 6], [5, 4, 3, 2]]
add(input1, input2)
Output:
[[10, 10, 'NULL'], [10, 10], [10, 10, 10, 10]]
add a comment
|
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2 Answers
2
active
oldest
votes
2 Answers
2
active
oldest
votes
active
oldest
votes
active
oldest
votes
How about:
def apply_f(a, b, f):
if isinstance(a, list):
return [apply_f(item_a, item_b, f) for item_a, item_b in zip(a, b)]
else:
return f(a, b)
result = apply_f(input1, input2, add)
add a comment
|
How about:
def apply_f(a, b, f):
if isinstance(a, list):
return [apply_f(item_a, item_b, f) for item_a, item_b in zip(a, b)]
else:
return f(a, b)
result = apply_f(input1, input2, add)
add a comment
|
How about:
def apply_f(a, b, f):
if isinstance(a, list):
return [apply_f(item_a, item_b, f) for item_a, item_b in zip(a, b)]
else:
return f(a, b)
result = apply_f(input1, input2, add)
How about:
def apply_f(a, b, f):
if isinstance(a, list):
return [apply_f(item_a, item_b, f) for item_a, item_b in zip(a, b)]
else:
return f(a, b)
result = apply_f(input1, input2, add)
answered Mar 28 at 21:30
Peter CollingridgePeter Collingridge
8,5273 gold badges34 silver badges54 bronze badges
8,5273 gold badges34 silver badges54 bronze badges
add a comment
|
add a comment
|
Assuming the lists are always the right length (you can put a check for this), make your function recursive:
def add(a, b):
if isinstance(a, list) and isinstance(b, list):
for a_sub, b_sub in zip(a, b):
return [add(a_sub, b_sub) for a_sub, b_sub in zip(a, b)]
elif "NULL" not in [a, b]:
return a + b
elif "NULL" in [a, b]:
return "NULL"
else:
raise ValueError("Wrong input shapes")
input1 = [[1, 2, "NULL"], [3, 4], [5, 6, 7, 8]]
input2 = [[9, 8, "NULL"], [7, 6], [5, 4, 3, 2]]
add(input1, input2)
Output:
[[10, 10, 'NULL'], [10, 10], [10, 10, 10, 10]]
add a comment
|
Assuming the lists are always the right length (you can put a check for this), make your function recursive:
def add(a, b):
if isinstance(a, list) and isinstance(b, list):
for a_sub, b_sub in zip(a, b):
return [add(a_sub, b_sub) for a_sub, b_sub in zip(a, b)]
elif "NULL" not in [a, b]:
return a + b
elif "NULL" in [a, b]:
return "NULL"
else:
raise ValueError("Wrong input shapes")
input1 = [[1, 2, "NULL"], [3, 4], [5, 6, 7, 8]]
input2 = [[9, 8, "NULL"], [7, 6], [5, 4, 3, 2]]
add(input1, input2)
Output:
[[10, 10, 'NULL'], [10, 10], [10, 10, 10, 10]]
add a comment
|
Assuming the lists are always the right length (you can put a check for this), make your function recursive:
def add(a, b):
if isinstance(a, list) and isinstance(b, list):
for a_sub, b_sub in zip(a, b):
return [add(a_sub, b_sub) for a_sub, b_sub in zip(a, b)]
elif "NULL" not in [a, b]:
return a + b
elif "NULL" in [a, b]:
return "NULL"
else:
raise ValueError("Wrong input shapes")
input1 = [[1, 2, "NULL"], [3, 4], [5, 6, 7, 8]]
input2 = [[9, 8, "NULL"], [7, 6], [5, 4, 3, 2]]
add(input1, input2)
Output:
[[10, 10, 'NULL'], [10, 10], [10, 10, 10, 10]]
Assuming the lists are always the right length (you can put a check for this), make your function recursive:
def add(a, b):
if isinstance(a, list) and isinstance(b, list):
for a_sub, b_sub in zip(a, b):
return [add(a_sub, b_sub) for a_sub, b_sub in zip(a, b)]
elif "NULL" not in [a, b]:
return a + b
elif "NULL" in [a, b]:
return "NULL"
else:
raise ValueError("Wrong input shapes")
input1 = [[1, 2, "NULL"], [3, 4], [5, 6, 7, 8]]
input2 = [[9, 8, "NULL"], [7, 6], [5, 4, 3, 2]]
add(input1, input2)
Output:
[[10, 10, 'NULL'], [10, 10], [10, 10, 10, 10]]
answered Mar 28 at 21:29
dzangdzang
6093 silver badges10 bronze badges
6093 silver badges10 bronze badges
add a comment
|
add a comment
|
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Will the lists only ever be nested one level deep?
– Peter Collingridge
Mar 28 at 21:08
@PeterCollingridge Yes, at least in the input stage (perhaps the output could be nested deeper depending on the function applied)
– AAC
Mar 28 at 21:24
If the lists are nested one level deep aways, why not
[func(val) for val in list_of_lists]
or eventmap(func, list_of_lists)
, it would simplify your function.– geckos
Mar 28 at 21:30