From: Ed Morton <mortonspam@...>
Date: 2011-05-20T08:20:29+09:00
Subject: Re: Linux utility with reverse index facility?

On May 17, 10:40 pm, Robert Nichols
<SEE_SIGNAT...@localhost.localdomain.invalid> wrote:
> On 05/16/2011 05:38 AM, no.top.p...@gmail.com wrote:
>
> > awk&stuff can "give me the the Nth element",
> > but, without writing your own search-loop,
> > what can "give me the index of the 'element'
> > which is<elementValue>" ?
>
> > I think it's called 'reverse indexing' ?
>
> In awk, it's just as easy to build an array where your "elementValues"
> are the indices and the values stored in the array are ordinal numbers.
> I,e., instead of
>      myArray[n++] = "cheese"
> have
>      myArray["cheese"] = n++
>
> Now you can use myArray["something"] in an expression and get back
> the number that was stored for that string (or a null string equivalent
> to arithmetic 0 if that index was never stored).
>
> --
> Bob Nichols         AT comcast.net I am "RNichols42"

not really robust though. consider what would happen if the same
string appeared twice in a record.