Re: gsub() is very slow in gawk 5.1.0

[Ed Morton]

On 7/14/2021 5:33 PM, Neil R. Ormos wrote:
> Ed Morton wrote:
>
> > On an online forum someone asked how to generate
> > a string of 100,000,000 "x"s.  They had tried
> > this in a BEGIN section:
> >     for(i=1;i<=100000000;i++) s = s "x"
> > and wanted to know if there was a better
> > approach. Someone suggested:
> >     s=sprintf("%*s",1000000000,""); gsub(/ /,"x",s)}
> > which is also what I'd have also suggested, but
> > upon testing that they found that the
> > sprintf+gsub approach was slower than the loop
> > in gawk 5.1.0 and while I couldn't reproduce
> > that exactly on cygwin, I can confirm that the
> > sprintf+gsub solution is much slower than I
> > expected: [...]
> I thought the original question was interesting,
> so I addressed it on the help-gawk@gnu.org list.
Thanks Neil - I personally wont be looking at anything on help-gawk but 
if you'd like to respond to the question that prompted the bug report, 
it's at https://stackoverflow.com/q/68371275/1745001.

    Ed.