Python 一维数组到二维数组的 Numpy 列表
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Numpy list of 1D Arrays to 2D Array
提问by David Folkner
I have a large list files that contain 2D numpy arrays pickled through numpy.save. I am trying to read the first column of each file and create a new 2D array.
我有一个很大的列表文件，其中包含通过numpy.save. 我正在尝试读取每个文件的第一列并创建一个新的二维数组。
I currently read each column using numpy.loadwith a mmap. The 1D arrays are now in a list.
我目前使用读每一列numpy.load有mmap。一维数组现在在一个列表中。
col_list = []
for f in file_list:
Temp = np.load(f,mmap_mode='r')
col_list.append(Temp[:,0])
How can I convert this into a 2D array?
如何将其转换为二维数组？
采纳答案by C. Yduqoli
You can use
您可以使用
numpy.stack(arrays, axis=0)
if you have an array of arrays. You can specify the axis in case you want to stack columns and not rows.
如果你有一个数组数组。如果要堆叠列而不是行，则可以指定轴。
回答by senshin
You can just call np.arrayon the list of 1D arrays.
您可以调用np.array一维数组列表。
>>> import numpy as np
>>> arrs = [np.array([1,2,3]), np.array([4,5,6]), np.array([7,8,9])]
>>> arrs
[array([1, 2, 3]), array([4, 5, 6]), array([7, 8, 9])]
>>> arr2d = np.array(arrs)
>>> arr2d.shape
(3, 3)
>>> arr2d
array([[1, 2, 3],
[4, 5, 6],
[7, 8, 9]])
回答by splendor
The array may be recreated:
可以重新创建数组：
a = np.array(a.tolist())
