{"id":190144,"date":"2023-05-10T10:41:22","date_gmt":"2023-05-10T14:41:22","guid":{"rendered":"https:\/\/ibkrcampus.com\/?p=190144"},"modified":"2023-05-10T10:41:45","modified_gmt":"2023-05-10T14:41:45","slug":"python-split-a-2d-array-vertically-and-convert-it-into-a-3d-array","status":"publish","type":"post","link":"https:\/\/www.interactivebrokers.com\/campus\/ibkr-quant-news\/python-split-a-2d-array-vertically-and-convert-it-into-a-3d-array\/","title":{"rendered":"Python: Split a 2d Array Vertically and Convert It into a 3d Array"},"content":{"rendered":"\n
This post shows how to split a 2d array into subsets of 2d arrays and convert them into a 3d array.<\/p>\n\n\n\n
The following figure shows what we want to do in this post.<\/p>\n\n\n\n<\/figure>\n\n\n\n
Exercise with code snippets<\/h3>\n\n\n\n
For example, let’ consider m<\/strong> which is a 2d array.<\/p>\n\n\n\n
# slice vertically 2d array and convert them to 3d array\n \nimport numpy as np\n \nm = np.array([[ 1, 2, 3, 4, 5, 6],\n [11,12,13,14,15,16],\n [21,22,23,24,25,26],\n [31,32,33,34,35,36],\n [41,42,43,44,45,46]])\nm<\/pre>\n\n\n\n
The following code examples split m (2d array) vertically into 2, 3, or 6 sub 2d arrays and concatenate them as a 3d array. The third argument of reshape() function is the number of sub columns. swapaxes(0,1)<\/strong> swaps .shape[0] and .shape[1].<\/p>\n\n\n\n
The only thing we do is just to select the number of sub columns.<\/strong><\/p>\n\n\n\n
# slice vertically 2d array and convert them to 3d array\n \n#1\nm.reshape(m.shape[0],-1, 3).swapaxes(0,1)\n#2\nm.reshape(m.shape[0],-1, 2).swapaxes(0,1)\n#3\nm.reshape(m.shape[0],-1, 1).swapaxes(0,1)<\/pre>\n\n\n\n
![\"\"](\"\/campus\/wp-content\/uploads\/sites\/2\/2023\/05\/slice_2d_array_to_3d_array-sh-fintech.png\")
<\/figure>\n\n\n\n