I have an array created by using
array1 = np.array([[25, 160, 154, 233],
[61, 244, 198, 248],
[227, 226, 141, 72 ],
[190, 43, 42, 8]],np.int) ;
which displays as
[[25, 160, 154, 233]
[61, 244, 198, 248]
[227, 226, 141, 72]
[190, 43, 42 , 8]]
How do I display this array as hexadecimal numbers like this:
[[0x04, 0xe0, 0x48, 0x28]
[0x66, 0xcb, 0xf8, 0x06]
[0x81, 0x19, 0xd3, 0x26]
[0xe5, 0x9a, 0x7a, 0x4c]]
Note: numbers in hex may not be real conversions of numbers in int. I have filled hex array just to give example of what I need.
You can set the print options for numpy to do this.
import numpy as np
np.set_printoptions(formatter={'int':hex})
np.array([1,2,3,4,5])
gives
array([0x1L, 0x2L, 0x3L, 0x4L, 0x5L])
The L at the end is just because I am on a 64-bit platform and it is sending longs to the formatter. To fix this you can use
np.set_printoptions(formatter={'int':lambda x:hex(int(x))})
Python has a built-in hex function for converting integers to their hex representation (a string). You can use numpy.vectorize to apply it over the elements of the multidimensional array.
>>> import numpy as np
>>> A = np.array([[1,2],[3,4]])
>>> vhex = np.vectorize(hex)
>>> vhex(A)
array([['0x1', '0x2'],
['0x3', '0x4']],
dtype='<U8')
There might be a built-in method of doing this with numpy which would be a better choice if speed is an issue.
Just throwing in my two cents you could do this pretty simply using list comprehension if it's always a 2d array like that
a = [[1,2],[3,4]]
print [map(hex, l) for l in a]
which gives you [['0x1', '0x2'], ['0x3', '0x4']]
This one-liner should do the job:
print '[' + '],\n['.join(','.join(hex(n) for n in ar) for ar in array1) + ']'
If what you're looking for it's just for display you can do something like this:
>>> a = [6, 234, 8, 9, 10, 1234, 555, 98]
>>> print '\n'.join([hex(i) for i in a])
0x6
0xea
0x8
0x9
0xa
0x4d2
0x22b
0x62
It should be possible to get the behavior you want with numpy.set_printoptions, using the formatter keyword arg. It takes a dictionary with a type specification (i.e. 'int') as key and a callable object returning the string to print. I'd insert code but my old version of numpy doesn't have the functionality yet. (ugh.)
array1_hex = np.array([[hex(int(x)) for x in y] for y in array1])
print array1_hex
# => array([['0x19', '0xa0', '0x9a', '0xe9'],
# ['0x3d', '0xf4', '0xc6', '0xf8'],
# ['0xe3', '0xe2', '0x8d', '0x48'],
# ['0xbe', '0x2b', '0x2a', '0x8']],
# dtype='|S4')
