numpy.arrays中的字符串预分配

Question

>>> import numpy as np
>>> a = np.array(['zero', 'one', 'two', 'three'])
>>> a[1] = 'thirteen'
>>> print a
['zero' 'thirt' 'two' 'three']
>>>

如您所见，第二个元素已被截断为原始数组中的最大字符数。

是否可以解决此问题？

Answer 1

如果您不知道最大长度元素，则可以使用dtype = object

>>> import numpy as np
>>> a = np.array(['zero', 'one', 'two', 'three'], dtype=object)
>>> a[1] = 'thirteen'
>>> print a
['zero' 'thirteen' 'two' 'three']
>>>

Answer 2

使用dtype中的numpy.array参数，例如：

>>> import numpy as np
>>> a = np.array(['zero', 'one', 'two', 'three'], dtype='S8')
>>> a[1] = 'thirteen'
>>> print(a)
['zero' 'thirteen' 'two' 'three']