Recipes for PDSC #3: Lists of Hashes

Declaration of a LIST OF HASHES:

@LoH = (        { 	  Lead      => "fred", 	  Friend    => "barney",        },       {	   Lead     => "george",	   Wife     => "jane",	   Son      => "elroy",       },       {	   Lead     => "homer",	   Wife     => "marge",	   Son      => "bart",       } );

Generation of a LIST OF HASHES:

# reading from file# format: LEAD=fred FRIEND=barneywhile ( <> ) {    $rec = {};    for $field ( split ) {	($key, $value) = split /=/, $field;	$rec->{$key} = $value;    }    push @LoH, $rec;}# reading from file# format: LEAD=fred FRIEND=barney# no tempwhile ( <> ) {    push @LoH, { split /[\s+=]/ };}# calling a function  that returns a key,value list, like# "lead","fred","daughter","pebbles"while ( %fields = getnextpairset() )     push @LoH, { %fields };}# likewise, but using no temp varswhile (<>) {    push @LoH, { parsepairs($_) };}# add key/value to an element$LoH[0]{"pet"} = "dino";$LoH[2]{"pet"} = "santa's little helper";

Access and Printing of a LIST OF HASHES:

# one element$LoH[0]{"lead"} = "fred";# another element$LoH[1]{"lead"} =~ s/(\w)/\u$1/;# print the whole thing with refsfor $href ( @LoH ) {    print "{ ";    for $role ( keys %$href ) {	print "$role=$href->{$role} ";    }    print "}\n";}# print the whole thing with indicesfor $i ( 0 .. $#LoH ) {    print "$i is { ";    for $role ( keys %{ $LoH[$i] } ) {	print "$role=$LoH[$i]{$role} ";    }    print "}\n";}# print the whole thing one at a timefor $i ( 0 .. $#LoH ) {    for $role ( keys %{ $LoH[$i] } ) {	print "elt $i $role is $LoH[$i]{$role}\n";    }}