Convert string to hex « Python recipes « ActiveState Code

Convert string to hex « Python recipes « ActiveState Code

    Convert string to hex (Python recipe) by Mykola Kharechko
    ActiveState Code (http://code.activestate.com/recipes/496969/)
    2
       

    Qoute string converting each char to hex repr and back
    Python, 14 lines
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    #convert string to hex
    def toHex(s):
        lst = []
        for ch in s:
            hv = hex(ord(ch)).replace('0x', '')
            if len(hv) == 1:
                hv = '0'+hv
            lst.append(hv)
       
        return reduce(lambda x,y:x+y, lst)

    #convert hex repr to string
    def toStr(s):
        return s and chr(atoi(s[:2], base=16)) + toStr(s[2:]) or ''

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    Tags: web
    6 comments
    sasa sasa 6 years, 4 months ago  # | flag

    list comprehensions. Though your snippet is nice, you should really have a look at least comprehensions. With a few built-in methods you can reduce your 8 lines of code (which is pretty slow because of the "extra work" I guess) to one:

    toHex = lambda x:"".join([hex(ord(c))[2:].zfill(2) for c in x])

    The builtin string-method "join" joins every element of the list to the string by re-using the string. ";;".join(['a', 'b', 'c']) would result in 'a;;b;;c'. Note that you can enhance the speed of the above snippet by replacing the [] with () what will change it from a list comprehension to a generator. Same enhancements can be done with your second function.

    Regards, Stargaming
    tomer filiba 6 years, 4 months ago  # | flag

    encode and decode. this functionality already exists with the encodings library (which is built-in):

    >>> "hello".encode("hex")
    '68656c6c6f'
    >>> "68656c6c6f".decode("hex")
    'hello'
    >>>

    Adam Monsen 5 years, 8 months ago  # | flag

    base 16 int conversion. The hex() and int() builtins should do everything you need...

    >>> int('0x10AFCC', 16)
    1093580
    >>> hex(1093580)
    '0x10afcc'

    Adam Monsen 5 years, 8 months ago  # | flag

    Nevermind, I should've read the original post more closely. As the other commenter said, str.encode() and str.decode() do the same thing as your code.
    a 2 years, 7 months ago  # | flag

    atoi() is deprecated. you should use int() instead
    sic_uk 2 years, 5 months ago  # | flag

    Even though modern Python implementations have .encode and .decode, old versions (pre v2) don't.

    My current Python platform (Telit GC864) runs on v1.5.2, with absolutely no option to upgrade.

    Thanks OP!