是否可以对行的插入进行矢量化?
我有一个大的2D numpy数组arr
(下面(和一个indices
列表。对于indices
中arr
的每个索引,我想在同一索引处将该索引处的行插入arr
行5次。
indices = [2, 4, 5, 9, 11, 12, 16, 18, 19]
目前,我只是循环浏览所有索引并插入新行。这种方法对于成千上万行的大列表来说很慢,所以出于性能原因,我想知道是否可以将这种多点瓦片类型的插入矢量化?
arr = [
[' ', ' ', 'd'],
[' ', 'd', ' '],
[' ', 'd', 'd'], # <-- reinsert arr[2] here 5 times
['d', ' ', ' '],
['d', ' ', 'd'], # <-- reinsert arr[4] here 5 times
['d', 'd', ' '], # <-- reinsert arr[5] here 5 times
['d', 'd', 'd'],
[' ', ' ', 'e'],
[' ', 'e', ' '],
[' ', 'e', 'e'], # <-- reinsert arr[9] here 5 times
['e', ' ', ' '],
['e', ' ', 'e'], # <-- reinsert arr[11] here 5 times
['e', 'e', ' '], # <-- reinsert arr[12] here 5 times
['e', 'e', 'e'],
[' ', ' ', 'f'],
[' ', 'f', ' '],
[' ', 'f', 'f'], # <-- reinsert arr[16] here 5 times
['f', ' ', ' '],
['f', ' ', 'f'], # <-- reinsert arr[18] here 5 times
['f', 'f', ' '] # <-- reinsert arr[19] here 5 times
]
首次插入所需结果的示例:
arr = [
[' ', ' ', 'd'],
[' ', 'd', ' '],
[' ', 'd', 'd'], # <-- arr[2]
[' ', 'd', 'd'], # <-- new insert
[' ', 'd', 'd'], # <-- new insert
[' ', 'd', 'd'], # <-- new insert
[' ', 'd', 'd'], # <-- new insert
[' ', 'd', 'd'], # <-- new insert
['d', ' ', ' ']
#...
]
您可以使用np.repeat
进行以下操作:
indices = [2, 4, 5, 9, 11, 12, 16, 18, 19]
rpt = np.ones(len(arr), dtype=int)
rpt[indices] = 5
np.repeat(arr, rpt, axis=0)