From: Robert Klemme <bob.news@...>
Date: 2005-03-19T21:59:51+09:00
Subject: Re: Iterating through a string and removing leading characters


"Christian Neukirchen" <chneukirchen@gmail.com> schrieb im Newsbeitrag 
news:m2vf7n28y0.fsf@lilith.local...
> Florian Gross <flgr@ccan.de> writes:
>
>> Randy Kramer wrote:
>>
>>>    * ?? (Is there any method which chops the first character from
>>> the string?  How efficient is that (especially compared to the
>>> method described in the next bullet).
>>
>> str.slice!(0)
>>
>> I think this is actually fairly efficient, but I suppose there's a
>> memmove involved at the C level.
>>
>> Perhaps you could set the characters you don't need to '\0' and remove
>> all of them after the iteration has ended with a Regexp?
>
> Better use String#delete! for that, no?

For removing \0 chars?  Yepp, that seems like an efficient way to do it. 
For direct removing slice! and String#[]= are most efficient:

>> Benchmark.bm do
?> end
      user     system      total        real
=> true
>> Benchmark.bm do |r|
?> r.report("slice!") do
?> 10000.times { "aaaaaaaaaaaaaa".slice!(0,5) }
>> end
>> r.report("[]=") do
?> 10000.times { "aaaaaaaaaaaaaa"[0,5]="" }
>> end
>> end
      user     system      total        real
slice!  0.140000   0.000000   0.140000 (  0.130000)
[]=  0.063000   0.000000   0.063000 (  0.065000)
=> true
>>

Kind regards

    robert