Question

我目前有一个NumPy数组，如下所示：

>>> print(a)
[[ 1.      26.9952  30.6501  10.06952  1.61731]
 [ 2.      26.9952  30.6501  10.06952  1.61731]
 [ 0.      26.9952  30.6501  10.06952  1.61731]
 [ 2.      26.9952  30.6501  10.06952  1.61731]
 [ 3.      26.9952  30.6501  10.06952  1.61731]
 [ 2.      26.9952  30.6501  10.06952  1.61731]
 [ 1.      26.9952  30.6501  10.06952  1.61731]
 [ 2.      26.9952  30.6501  10.06952  1.61731]
 [ 3.      26.9952  30.6501  10.06952  1.61731]
 [ 2.      26.9952  30.6501  10.06952  1.61731]]

我有一本这样的字典：

map_dict = {0.0: 'a', 1.0: 'b', 2.0: 'c', 3.0: 'd'}

我想做的是将NumPy数组a的第一列中的所有值转换为map_dict中的相应值。有什么有效的方法可以做到吗？我正在使用的当前方法是通过for循环，并在进行过程中迭代地替换值。

Answer 1

您可以尝试np.vectorize：

>>> import numpy as np
>>> a = np.arange(12).reshape(4,3)
>>> a
array([[ 0,  1,  2],
       [ 3,  4,  5],
       [ 6,  7,  8],
       [ 9, 10, 11]])
>>> map_dict = {0.0: 'a', 3.0: 'b', 6.0: 'c', 9.0: 'd'}
>>> a = a.astype(object)
>>> a[:,0] = np.vectorize(map_dict.get)(a[:,0])
>>> a
array([['a', 1, 2],
       ['b', 4, 5],
       ['c', 7, 8],
       ['d', 10, 11]], dtype=object)

将NumPy数组条目映射到字典值

1 个答案: