string processing - some problems whenever I have to parse a more complex string
Ned Batchelder
ned at nedbatchelder.com
Tue Oct 21 14:23:22 EDT 2014
On 10/21/14 10:32 AM, CWr wrote:
> Is there any implementation like C++ StringPiece class? Or something like the following behavior:
>
>
>>>> >>>s = StringSlice('abcdef')
>>>> >>>s
> StringSlice('abcdef') at xxx
>>>> >>>s[0]
> 'a'
>>>> >>>s.chop(1) # chop the first item
>>>> >>>s[0] # 'b' is the new first item
> 'b'
>>>> >>>s[:2]
> 'bc'
>>>> >>>s.chop(-1) # chop the last item
>>>> >>>s[-1]
> 'e'
>>>> >>>s[1:]
> 'cde'
>>>> >>>while s[0] != 'e':
> s.chop(1)
>>>> >>>s[0]
> 'e'
>>>> >>>s.startswith('e')
> True
>>>> >>>s.isdigit()
> False
You could certainly implement a StringSlice object that worked like
this. Store the string, the start and end indexes. Override
__getitem__ to adjust indexes and slice endpoints, implement chop() to
change the start or end indexes. Implementing the string operations
would get messy, likely you would materialize the sliced string to make
them work.
--
Ned Batchelder, http://nedbatchelder.com
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