[jcd at sdf.lonestar.org: Re: Compress a string]

[Matt Porter]

On Sun, 18 May 2008 19:13:57 +0100, J. Clifford Dyer  
<jcd at sdf.lonestar.org> wrote:

> On Sun, May 18, 2008 at 07:06:10PM +0100, Matt Porter wrote regarding  
> Compress a string:
>>
>> Hi guys,
>>
>> I'm trying to compress a string.
>> E.g:
>>  "AAAABBBC" -> "ABC"
>>
>> The code I have so far feels like it could be made clearer and more
>> succinct, but a solution is currently escaping me.
>>
>>
>> def compress_str(str):
>>     new_str = ""
>>     for i, c in enumerate(str):
>>         try:
>>             if c != str[i+1]:
>>                 new_str += c
>>         except IndexError:
>>             new_str += c
>>     return new_str
>>
>>
>> Cheers
>> Matt
>
> def compress_str(s):
>     # str is a builtin keyword. Don't overload it.
> 	out = []
> 	for c in s:
> 		if out and c == out[-1]:
> 			out.append(c) # This is faster than new_str += c
> 	return ''.join(out)
>
>

Thanks. Had to change a few bits to make it behave as I expected:

def compress_str(s):
     # str is a builtin keyword. Don't overload it.
     out = [s[0],]
     for c in s:
         if out and c != out[-1]:
             out.append(c) # This is faster than new_str += c
     return ''.join(out)

Feels slightly less hacked together


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