无法将numpy 2d数组保存到fi中

Question

我有以下二维numpy矩阵，它是两个矩阵的串联：

     >>> mnist1_train_final_data=np.hstack((y_train_mnist_ni,features_train_mnist1))
     >>> type(mnist1_train_final_data)
     <type 'numpy.ndarray'>
     >>> mnist1_train_final_data.dtype
     dtype('S32')
     >>> mnist1_train_final_data.shape
      (1149, 129)

如您所见，它是一个二维numpy数组。但是，当我尝试使用以下命令保存它时：

>>> np.savetxt('test.txt', mnist1_train_final_data, delimiter=',', fmt='%5.2f') 

它显示以下错误：

Traceback (most recent call last):   File "<stdin>", line 1, in
<module>   File "/usr/lib/python2.7/site-packages/numpy/lib/npyio.py",
line 1162, in savetxt
    % (str(X.dtype), format)) TypeError: Mismatch between array dtype ('|S32') and format specifier
('%5.2f,%5.2f,%5.2f,%5.2f,%5.2f,%5.2f,%5.2f,%5.2f,%5.2f,%5.2f,%5.2f,%5.2f,%5.2f,%5.2f,%5.2f,%5.2f,%5.2f,%5.2f,%5.2f,%5.2f,%5.2f,%5.2f,%5.2f,%5.2f,%5.2f,%5.2f,%5.2f,%5.2f,%5.2f,%5.2f,%5.2f,%5.2f,%5.2f,%5.2f,%5.2f,%5.2f,%5.2f,%5.2f,%5.2f,%5.2f,%5.2f,%5.2f,%5.2f,%5.2f,%5.2f,%5.2f,%5.2f,%5.2f,%5.2f,%5.2f,%5.2f,%5.2f,%5.2f,%5.2f,%5.2f,%5.2f,%5.2f,%5.2f,%5.2f,%5.2f,%5.2f,%5.2f,%5.2f,%5.2f,%5.2f,%5.2f,%5.2f,%5.2f,%5.2f,%5.2f,%5.2f,%5.2f,%5.2f,%5.2f,%5.2f,%5.2f,%5.2f,%5.2f,%5.2f,%5.2f,%5.2f,%5.2f,%5.2f,%5.2f,%5.2f,%5.2f,%5.2f,%5.2f,%5.2f,%5.2f,%5.2f,%5.2f,%5.2f,%5.2f,%5.2f,%5.2f,%5.2f,%5.2f,%5.2f,%5.2f,%5.2f,%5.2f,%5.2f,%5.2f,%5.2f,%5.2f,%5.2f,%5.2f,%5.2f,%5.2f,%5.2f,%5.2f,%5.2f,%5.2f,%5.2f,%5.2f,%5.2f,%5.2f,%5.2f,%5.2f,%5.2f,%5.2f,%5.2f,%5.2f,%5.2f,%5.2f,%5.2f,%5.2f,%5.2f')

在我的案例中，如何保存二维numpy矩阵？你知道吗

Answer 1

S32是字符串类型。您指定的格式是针对浮点类型的。要保存字符串类型，使用savetxt需要传递"%s"格式化程序。请注意，默认格式对字符串类型无效，因此必须传递有效的字符串格式化程序，如"%s"

np.savetxt('test.txt', mnist1_train_final_data, delimiter=',', fmt='%s')