Storing string in numpy matrix

Question

I create the following:

a=np.eye(2, dtype='S17')

But when I print it I get:

print(a)
[[b'1' b'']
 [b'' b'1']]

Why does it happen and what I can do to just get the strings without b? Or should I change the way of introducing the data or the dtype?

The desired output would be:

[['1' '']
 ['' '1']]

So that I can replace this strings by others

Because I want to store strings there, therefore when I create the matrix I first say what type of data I will put inside and then add it. — llrs, Jan 24 '14 at 18:42
http://stackoverflow.com/questions/6269765/what-does-the-b-character-do-in-front-of-a-string-literal — Karoly Horvath, Jan 24 '14 at 18:46

score 2 · Accepted Answer · answered Jan 24 '14 at 18:49

You can use numpy.char.decode to decode the bytes literal:

In [1]: import numpy as np

In [2]: a = np.eye(2, dtype='S17')                                                                                   

In [3]: a
Out[3]: 
array([[b'1', b''],                                                                                                
       [b'', b'1']],                                                                                               
      dtype='|S17')                                                                                                

In [4]: np.char.decode(a, 'ascii')                                                                                 
Out[4]: 
array([['1', ''],                                                                                                  
       ['', '1']],                                                                                                 
      dtype='<U1')

Instead of `dtype='S17'` changing it to `' – llrs Jan 24 '14 at 19:04 — llrs, Jan 24 '14 at 19:04

Storing string in numpy matrix

1 Answers1