将字段追加到大小为ONE的结构化数组时出现TypeError [英] TypeError when appending fields to a structured array of size ONE

问题描述

尝试将字段追加到大小为ONE的结构化数组时遇到运行时错误.我在下面写了一个简单的例子:

I'm getting a run-time error when trying to append field(s) to a structured array of size ONE. I've written a simple example below:

import numpy as np
import numpy.lib.recfunctions as rcfuncs

dtype_ = np.dtype( { 'names': ["field_a","field_b","field_c"]
                  , 'formats': ['S32', 'i4', 'f8']}
                  )
data_ = [("1",17, 123.45)]
numpy_array = np.array(data_, dtype_)            

# append 2 fields
numpy_array = rcfuncs.append_fields( numpy_array,["field_d","field_e"],data=[ "1","3" ] )

# append 1 field fails :(
numpy_array = rcfuncs.append_fields( numpy_array, "field_f", data=["123456"] )

我遇到了错误:

TypeError: descriptor 'ravel' requires a 'numpy.ndarray' object but received a 'numpy.void'

同样，如果我反转"附加内容，则包含两个字段的语句将失败:

As well, if I 'invert' the appends, the statement with the two fields append will fail:

# append 1 field
numpy_array = rcfuncs.append_fields( numpy_array, "field_f", data=["123456"] )

# append 2 fields fails :(
numpy_array = rcfuncs.append_fields( numpy_array,["field_d","field_e"],data=[ "1", "3" ] )

我正在使用python 2.7.11和numpy 1.11.0运行，并且初始数组的大小大于2时我没有问题.

I am running with python 2.7.11 and numpy 1.11.0 and I do not have the issue when the initial array is of size greater than 2.

如何解决类型错误?

谢谢

推荐答案

将可选参数usemask设置为False时，我们没有收到TypeError错误.

We do not get the TypeError when setting the optional parameter usemask to False

numpy_array = \
  rcfuncs.append_fields(numpy_array, "field_f", data=["123456"], usemask=False)
numpy_array = \
  rcfuncs.append_fields(numpy_array,["field_d","field_e"],data=[ "1", "3" ], usemask=False)

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