Re: awk challenge

A Ferenstein <epaalx@hotmail.com> wrote:
> Here's the task: create an array containing beginning and end of columns (
of
> some text not matching a regexp string) separated by a regexp string.
> Condition: can't use substr() to read character-by-character!
>
> For example, let's say regexp=" " (ie. a space), result "delimiter_array"
> (where x represents some character not matched by regexp):
>
> xxx    xxxx  xxxxx
>
> would result in
>  delimiter_array[1] is 1
>  delimiter_array[2] is 3
>  delimiter_array[3] is 6
>  delimiter_array[4] is 9
>  delimiter_array[5] is 11
>  delimiter_array[6] is 15

You example doesn't match your numbers.  Count again, and repost.

William Park wrote:
> A Ferenstein <epaalx@hotmail.com> wrote:
> 
>
>
> You example doesn't match your numbers.  Count again, and repost.

Or not :-). Don't know about anyone else but IMHO "let's see how clever
you are" exercises are just newsgroup clutter. In that category I
include anything that says "solve this without doing ABC" without a good
reason for that restriction.

Ed.

In article <cn08hr$llc@netnews.proxy.lucent.com>,
Ed Morton  <morton@lsupcaemnt.com> wrote:
...
>Or not :-). Don't know about anyone else but IMHO "let's see how clever
>you are" exercises are just newsgroup clutter. In that category I include
>anything that says "solve this without doing ABC" without a good reason
>for that restriction.

You are obviously an engineer and not a mathematician.

I need say no more.

Kenny McCormack wrote:

> In article <cn08hr$llc@netnews.proxy.lucent.com>,
> Ed Morton  <morton@lsupcaemnt.com> wrote:
> ...
> 
>
>
> You are obviously an engineer and not a mathematician.

He shoots, he scores. Guilty as charged.

> I need say no more.

A mathematician would have found a way to say "I need say no more"
without using vowels.

Ed.

The reason for not using substr() character-by-character is self evident
(clue. 'very big line'), neither would it exploit awk's strengths -
optimised functions related to strings. Plus the aim of exercise to think
rather than force.
Please look at my version of solution.

> Or not :-). Don't know about anyone else but IMHO "let's see how clever
> you are" exercises are just newsgroup clutter. In that category I
> include anything that says "solve this without doing ABC" without a good
> reason for that restriction.

In article <cn1qeh$m5s$1@newstree.wise.edt.ericsson.se>,
A Ferenstein <epaalx@hotmail.com> wrote:
>The reason for not using substr() character-by-character is self evident
>(clue. 'very big line'), neither would it exploit awk's strengths -
>optimised functions related to strings. Plus the aim of exercise to think
>rather than force.
>Please look at my version of solution.

Ed has made it clear that he is a simpleton who doesn't like theoretical
problems.  You are unlikely to change his way of thinking (or not).
 

Kenny McCormack wrote:
> In article <cn1qeh$m5s$1@newstree.wise.edt.ericsson.se>,
> A Ferenstein <epaalx@hotmail.com> wrote:
> 

The clue appears to be missing from your original posting. Had you said
"I have a problem where my lines are very long and using substr() takes
too long because XYZ - is there a way to optimizes this code" then we
wouldn't be having this chat.

neither would it exploit awk's strengths - 

But it does exploit awk's strengths -
a rich set of component functions from which you can quickly and easily
build solutions to problems. No-ones using awk vs C for it's speed of
execution.

Plus the aim of exercise to think 

I suspect most of us get a reasonable workout every day solving real
problems and don't need the additional exercise.
 

I did. It's not immediately obvious that a recursive solution with
multiple calls to "match()" would be any faster than using substr().

>
> Ed has made it clear that he is a simpleton who doesn't like theoretical
> problems.  You are unlikely to change his way of thinking (or not).

Yes, exactly. Hey, hang on.... I need to go ask someone if that's an insult.

Ed.

> 
>
>

A Ferenstein wrote: 
>
>
> Given that column separators are regexp's, match() is un-avoidable.
>
>

No it isn't:

gawk '{c=gsub("\(.\)","&"SUBSEP);FS=SUBSEP;$0=$0;idx=1;
for (i=1; i<NF; i++) {
if ($i == " ") {
if (fnd) {
delimiter_array[++idx] = i-1
idx++;
}
fnd = 0
} else {
if (!fnd) {
delimiter_array[idx] = i
}
fnd = 1
}
}
delimiter_array[++idx] = i-1
}'

I have no idea if the above is any faster or slower than using substr()
or your recusrion with match(). My only point is that there's alternatives.

Regards,

Ed.

Kenny McCormack wrote:

> In article <cn08hr$llc@netnews.proxy.lucent.com>,
> Ed Morton  <morton@lsupcaemnt.com> wrote:
> ...
> 
>
>
> You are obviously an engineer and not a mathematician.

He shoots, he scores. Guilty as charged.

> I need say no more.

A mathematician would have found a way to say "I need say no more"
without using vowels.

Ed.

In article <cn1qeh$m5s$1@newstree.wise.edt.ericsson.se>,
A Ferenstein <epaalx@hotmail.com> wrote:
>The reason for not using substr() character-by-character is self evident
>(clue. 'very big line'), neither would it exploit awk's strengths -
>optimised functions related to strings. Plus the aim of exercise to think
>rather than force.
>Please look at my version of solution.

Ed has made it clear that he is a simpleton who doesn't like theoretical
problems.  You are unlikely to change his way of thinking (or not).