Numpy Integer Array to Hex String Array without "0x"

Question

array([(1, 1, 0, 2, 240), (1, 1, 0, 255, 255), (1, 1, 0, 255, 255), ...,
       (1, 1, 0, 255, 255), (1, 1, 0, 255, 255), (1, 1, 0, 255, 60)],
      dtype=[('A','u1'), ('B','u1'), ('C','u1'), ('D','u1'), ('E','u1')])

I have a numpy array as shown above and I want to print them to a file in HEX like so:

1 1 0 02 EF
1 1 0 FF FF
...
1 1 0 FF FF
1 1 0 FF 3C

The integer values of the left most 3 columns are only 0 and 1 so they should only have 1 HEX characters. The rightmost 2 columns both should have 2 HEX characters even if their integer value requires only 1. The "0x" prefix should be omitted.

The straightforward way is to use for loop and format the strings but the data set is huge and it takes a very long time to complete. Is there a fast numpy way to do build the string array and then output it to file?

It will be way easier to do that if your data where stored as a 2D array and not as a structured arrays, why are you using a structured array since you do not have mixed datatype ? — obchardon
– obchardon, Commented Apr 22, 2021 at 10:51
The data is read in from a binary file into a structured array. The data fields in the binary file have different lengths. How do I read in the data from the binary file into 2D array instead of structured array? — bFig8
– bFig8, Commented Apr 22, 2021 at 11:01

bFig8 · Accepted Answer · 2021-04-22 11:02:28Z

1

Ok I did some more work on this and I found this solution that worked for me:

numpy.savetxt("my_file.txt", my_numpy_structured_array, delimiter=" ", fmt="%x %x %x %02x %02x")

answered Apr 22, 2021 at 11:02

bFig8

4273 gold badges8 silver badges20 bronze badges

Add a comment |

Collectives™ on Stack Overflow

Numpy Integer Array to Hex String Array without "0x"

1 Answer 1

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

1 Answer 1

Your Answer

Sign up or log in

Post as a guest

Related