How to remove '\x' from a hex string in Python?

Question

I'm reading a wav audio file in Python using wave module. The readframe() function in this library returns frames as hex string. I want to remove \x of this string, but translate() function doesn't work as I want:

>>> input = wave.open(r"G:\Workspace\wav\1.wav",'r')
>>> input.readframes (1)
'\xff\x1f\x00\xe8'
>>> '\xff\x1f\x00\xe8'.translate(None,'\\x')
'\xff\x1f\x00\xe8'
>>> '\xff\x1f\x00\xe8'.translate(None,'\x')
ValueError: invalid \x escape
>>> '\xff\x1f\x00\xe8'.translate(None,r'\x')
'\xff\x1f\x00\xe8'
>>>

Any way I want divide the result values by 2 and then add \x again and generate a new wav file containing these new values. Does any one have any better idea?

What's wrong?

score 5 · Answer 1 · answered Nov 14 '15 at 11:42

One way to do what you want is:

>>> s = '\xff\x1f\x00\xe8'
>>> ''.join('%02x' % ord(c) for c in s)
'ff1f00e8'

The reason why translate is not working is that what you are seeing is not the string itself, but its representation. In other words, \x is not contained in the string:

>>> '\\x' in '\xff\x1f\x00\xe8'
False

\xff, \x1f, \x00 and \xe8 are the hexadecimal representation of for characters (in fact, len(s) == 4, not 24).

Dmitry · Accepted Answer · 2015-11-14T12:45:18.507

5

Indeed, you don't have backslashes in your string. So, that's why you can't remove them.

If you try to play with each hex character from this string (using ord() and len() functions - you'll see their real values. Besides, the length of your string is just 4, not 16.

You can play with several solutions to achieve your result: 'hex' encode:

'\xff\x1f\x00\xe8'.encode('hex')
'ff1f00e8'

Or use repr() function:

repr('\xff\x1f\x00\xe8').translate(None,r'\\x')

edited Nov 14 '15 at 12:45

answered Nov 14 '15 at 12:12

Dmitry

432
2
6

Does it have any reverse way to? I mean how can I convert 'ff1f00e8' to '\xff\x1f\x00\xe8' again? any Decode function? – Ebrahim Ghasemi Nov 14 '15 at 12:37
3

Reverse: `'ff1f00e8'.decode('hex')` :) What about length - was playing with backslashes in the initial string. – Dmitry Nov 14 '15 at 12:40

score 3 · Answer 3 · answered Nov 14 '15 at 11:44

3

Use the encode method:

>>> s = '\xff\x1f\x00\xe8'
>>> print s.encode("hex")
'ff1f00e8'

answered Nov 14 '15 at 11:44

Omer Eldan

1,757
1
11
10

score 0 · Answer 4 · answered Nov 14 '15 at 11:44

0

As this is a hexadecimal representation, encode with hex

>>> '\xff\x1f\x00\xe8'.encode('hex')
'ff1f00e8'

answered Nov 14 '15 at 11:44

Ahsanul Haque

10,676
4
41
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How to remove '\x' from a hex string in Python?

4 Answers4

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