in reply to Re: To use a module...or not.
in thread To use a module...or not.

The problem is how to flatten the nested hash keys and then reconstitute them? (+ availability:)

Examine what is said, not who speaks.
"Efficiency is intelligent laziness." -David Dunham
"Think for yourself!" - Abigail
"Memory, processor, disk in that order on the hardware side. Algorithm, algoritm, algorithm on the code side." - tachyon

Replies are listed 'Best First'.
Re^3: To use a module...or not.
by diotalevi (Canon) on Jul 26, 2004 at 02:55 UTC
Step backwards in time and rediscover fixed length records.

I've taken a few days to think about this and I still don't get what you mean. Sarcasm or sage advice? Maybe you could expland this a little?

Examine what is said, not who speaks.
"Efficiency is intelligent laziness." -David Dunham
"Think for yourself!" - Abigail
"Memory, processor, disk in that order on the hardware side. Algorithm, algoritm, algorithm on the code side." - tachyon

That wasn't sarcasm. I meant that if you mean to flatten a multi-level key into a string you find out the maximum length of each key component (or truncate and pad) and join them together in the proper order after padding. I include both a Lotus Domino @Formula and some perl code because I find both to be really, really typical. The Lotus Domino code is a bit simpler because the sorting is actually occuring just outside of this snippet in a View so all you see here is the serialization of a single record's keys.

```REM { Sorting by three values for Lotus Domino (in a single view colum
+n). }
MaxLength := 255;

@Implode( @Transform(
A : B : C;
"key";
@If(
@Length( key ) > 255;
@Left( key; MaxLength );
key + @Repeat( @Char( 0 ); MaxLength - @Length( key ) ) )
```# Sorting a three level hash in perl
my \$a_len = max( map length(),
keys %h );
my \$b_len = max( map length(),
map keys %\$_,
values %h );
my \$c_len = max( map length(),
map keys %\$_,
map values %\$_,
values %h );
my \$fmt = "a\$a_len a\$b_len a\$c_len";

# Assumes \0 is not present in any keys
my @sorted_keys =
( map [ unpack( "a\$a_len a\$b_len a\$c_len ",
\$_ ) ],
sort
map( {
my \$a = \$_;
map( {
my \$b = \$_;
map( { pack( "a\$a_len a\$b_len a\$c_len",
\$a,      \$b      \$_ ) }
keys %{ \$h{ \$a }{ \$b } } )
} keys %{ \$h{ \$a } } )
} keys %h );