Python Add Elements of a List (or Set, or whatever Data Type is appropriate)
Pergunta
Is there an easy way to add the members of two equally sized list
s (or tuple
or whatever data type would work best)?
I have, for example a
and b
with 2 elements:
a = (0, 10)
b = (0, -10)
I want to add them and get as result:
result = (0, 0)
NOT (0, 10, 0, -10)
Solução
You can do this in one line in Python:
map(sum, zip(A, B))
Example:
>>> B = [1, 2, 3, 4]
>>> C = [1, 2, 4, 8]
>>> map(sum, zip(B, C))
[2, 4, 7, 12]
Outras dicas
Three options:
>>> [a+b for (a,b) in zip(A,B)]
>>> map(int.__add__, A, B)
>>> map(sum, zip(A,B))
if you want to operate with list of numbers use numpy
>>> a = [1,2]
>>> b = [1,2]
>>> import numpy as np
>>> np.add(a,b)
array([2, 4])
>>>
You can use numpy to add the lists:
add(array([-1.2, 1.2]), array([1,3]))
and the result it:
array([-0.2, 4.2])
List ANSWER = ()
for index in range(0, len(A))
ANSWER.append(A[index]+B[index])
yes, just do this
map(sum,zip(A,B)
or, (actually clearly faster)
u=map(lambda a,b:a+b,A,B)
Timing examples:
A=range(3000)
B=range(3000)
for i in range(15000):
u=map(lambda a,b:a+b,A,B) # takes about 7.2 seconds
# u=map(sum,zip(A,B)) # takes about 11 seconds
# u=map(int.__add__,A,B) # (Edward Loper) actually also consistently ~0.5 sec slower than lambda
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