[英]How to append a column to a 2d numpy array in Python 2.7?
I have two numpy arrays. 我有两个numpy数组。 One is a 2d matrix that has 3 columns and 4 rows.
一个是2d矩阵,有3列4行。 The second numpy array is a 1d array with 4 values.
第二个numpy数组是一个包含4个值的1d数组。 Is there a way to append the second numpy array as a column to the first numpy array in Python 2.7?
有没有办法将第二个numpy数组作为列附加到Python 2.7中的第一个numpy数组?
For example if these were my two numpy arrays: 例如,如果这些是我的两个numpy数组:
arr2d = np.matrix(
[[1, 2, 3],
[4, 5, 6],
[7, 8, 9],
[10, 11, 12]])
column_to_add = np.array([10, 40, 70, 100])
I'd like the output to look like this 我希望输出看起来像这样
[[1, 2, 3, 10],
[4, 5, 6, 40],
[7, 8, 9, 70],
[10, 11, 12, 100]]
I tried using 我试过用
output = np.hstack((arr2d, column_to_add))
but I got an error that says: 但我得到一个错误,上面写着:
ValueError: all the input arrays must have the same number of dimensions.
Any and all help is appreciated. 任何和所有的帮助表示赞赏。 Thank you so much!
非常感谢!
You can use numpy.column_stack
: 你可以使用
numpy.column_stack
:
import numpy as np
arr2d = np.matrix(
[[1, 2, 3],
[4, 5, 6],
[7, 8, 9],
[10, 11, 12]])
column_to_add = np.array([10, 40, 70, 100])
output = np.column_stack((arr2d, column_to_add))
Output: 输出:
matrix([[ 1, 2, 3, 10],
[ 4, 5, 6, 40],
[ 7, 8, 9, 70],
[ 10, 11, 12, 100]])
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