分配给NumPy中的列? [英] Assigning to columns in NumPy?

问题描述

如何使用NumPy编写以下MATLAB代码?

How could the following MATLAB code be written using NumPy?

A = zeros(5, 100);
x = ones(5,1);
A(:,1) = x;

分配行似乎很容易，但是我找不到将数组分配给另一个数组的列的示例.

Assigning to rows seems to work easily, but I couldn't find an example of assigning an array to a column of another array.

推荐答案

使用a[:,1] = x[:,0].您需要x[:,0]来选择x的列作为单个numpy数组.如果您可以选择x的格式，最好不要首先使其成为二维数组，而要使其成为常规的(行)数组:

Use a[:,1] = x[:,0]. You need x[:,0] to select the column of x as a single numpy array. If you have the choice of how to format x, it's better to not make it a 2-dimensional array in the first place, but just a regular (row) array:

>>> a
array([[ 0.,  0.,  0.],
       [ 0.,  0.,  0.],
       [ 0.,  0.,  0.],
       [ 0.,  0.,  0.],
       [ 0.,  0.,  0.]])
>>> x = numpy.ones(5)
>>> x
array([ 1.,  1.,  1.,  1.,  1.])
>>> a[:,1] = x
>>> a
array([[ 0.,  1.,  0.],
       [ 0.,  1.,  0.],
       [ 0.,  1.,  0.],
       [ 0.,  1.,  0.],
       [ 0.,  1.,  0.]])

这篇关于分配给NumPy中的列?的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！