Fastest way to remove the first x characters from a very long string

[Chris Angelico]

On Sun, May 17, 2015 at 2:22 AM,  <bruceg113355 at gmail.com> wrote:
> # Original Approach
> # -----------------
> ss = ss.split("\n")
> ss1 = ""
> for sdata in ss:
>     ss1 = ss1 + (sdata[OFFSET:] + "\n")
>
>
> # Chris's Approach
> # ----------------
> lines = ss.split("\n")
> new_text = "\n".join(line[8:] for line in lines)

Ah, yep. This is exactly what str.join() exists for :) Though do make
sure the results are the same for each - there are two noteworthy
differences between these two. Your version has a customizable OFFSET,
where mine is hard-coded; I'm sure you know how to change that part.
The subtler one is that "\n".join(...) won't put a \n after the final
string - your version ends up adding one more newline. If that's
important to you, you'll have to add one explicitly. (I suspect
probably not, though; ss.split("\n") won't expect a final newline, so
you'll get a blank entry in the list if there is one, and then you'll
end up reinstating the newline when that blank gets joined in.) Just
remember to check correctness before performance, and you should be
safe.

ChrisA