[英]How do I combine two numpy arrays element wise in python?
I have two numpy arrays: 我有两个numpy数组:
A = np.array([1, 3, 5, 7])
B = np.array([2, 4, 6, 8])
and I want to get the following from combining the two: 我想从两者结合得到以下内容:
C = [1, 2, 3, 4, 5, 6, 7, 8]
I'm able to get something close by using zip
, but not quite what I'm looking for: 我可以通过使用
zip
获得一些东西,但不是我正在寻找的东西:
>>> zip(A, B)
[(1, 2), (3, 4), (5, 6), (7, 8)]
How do I combine the two numpy arrays element wise? 我如何组合两个numpy数组元素?
I did a quick test of 50,000 elements in each array (100,000 combined elements). 我对每个阵列中的50,000个元素进行了快速测试(100,000个组合元素)。 Here are the results:
结果如下:
User Ma3x: Time of execution: 0.0343832323429 Valid Array?: True
User mishik: Time of execution: 0.0439064509613 Valid Array?: True
User Jaime: Time of execution: 0.02767023558 Valid Array?: True
Tested using Python 2.7, Windows 7 Enterprise 64-bit, Intel Core i7 2720QM @2.2 Ghz Sandy Bridge, 8 GB Mem 使用Python 2.7,Windows 7企业版64位,英特尔酷睿i7 2720QM @ 2.2 Ghz Sandy Bridge,8 GB Mem进行测试
You can also use slices : 你也可以使用切片:
C = np.empty((A.shape[0]*2), dtype=A.dtype)
C[0::2] = A
C[1::2] = B
>>> import numpy as np
>>> A=np.array([1,3,5,7])
>>> B=np.array([2,4,6,8])
>>> C=np.dstack([A,B])
>>> D=C.reshape((1,8))[0]
>>> D
array([1, 2, 3, 4, 5, 6, 7, 8])
Some answers suggested sorting, but since you want to combine them element-wise sorting won't achieve the same result. 一些答案建议排序,但由于你想要将它们组合在一起,因此元素排序将无法实现相同的结果。
Here is one way to do it 这是一种方法
C = []
for elem in zip(A, B):
C.extend(elem)
You can try this: 你可以试试这个:
C = sorted(A.tolist() + B.tolist())
A.tolist()
will yield [1, 3, 5, 7]
A.tolist()
将产生[1, 3, 5, 7]
B.tolist()
will yield [2, 4, 6, 8]
B.tolist()
会产生[2, 4, 6, 8]
A.tolist() + B.tolist()
- [1, 3, 5, 7, 2, 4, 6, 8]
A.tolist() + B.tolist()
- [1, 3, 5, 7, 2, 4, 6, 8]
A.tolist() + B.tolist()
[1, 3, 5, 7, 2, 4, 6, 8]
sorted(...)
- [1, 2, 3, 4, 5, 6, 7, 8]
sorted(...)
- [1, 2, 3, 4, 5, 6, 7, 8]
Without sorting: 没有排序:
C = [y for x in zip(A, B) for y in x]
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