Re^2: Learning about Arrays and Hashes - printing pieces of them

Hi Mom!

I see my dog forgot to point to my hound.... I was missing the > pointing to hound. Thank you!

What happens when I try:

print $rec -> [Buick], "\n";
[download]

Does that just print "Buick" or does it print a 0? I didn't find a specific example of that so I was wondering how I find the value Buick.

Could I do something like this:

my $favoriteCar = $rec->{LOOKUP}[0];
print "My favorite car is ", $favoriteCar, "\n";
[download]

Thank you!

Raye Ann

Comment on Re^2: Learning about Arrays and Hashes - printing pieces of them Select or Download Code

Replies are listed 'Best First'.
Re^3: Learning about Arrays and Hashes - printing pieces of them by NetWallah (Canon) on Jan 28, 2015 at 20:10 UTC
You can answer these questions by running the code yourself, under the perl built-in debugger. Just run you rprogam like this: `perl -d <Your-program-file-name>` [download] Inside the debugger prompt , use the "h" (help) command , using "x" check the values of the variables. Note: You need to FIRST use the "s" command to get the $rec variable initialized. Here are the results of running your program - it includes answers to your questions: `DB<1> s main::(junk.pl:10): print $rec->{TEXT},"\n", main::(junk.pl:11): $rec->{SEQUENCE}[0],"\n", main::(junk.pl:12): $rec->{LOOKUP}{"dog"},"\n"; DB<1> x $rec -> [Buick] Not an ARRAY reference at (eval 7)[/usr/lib/perl5/5.10.0/perl5db.pl:63 +8] line 2. DB<2> x $rec -> {LOOKUP} -> {cars} 0 'Buick' DB<3> x $rec -> {LOOKUP} [0] Not an ARRAY reference at (eval 9)[/usr/lib/perl5/5.10.0/perl5db.pl:63 +8] line 2. DB<4> x $rec -> {LOOKUP} {dog} 0 'hound' DB<5> q` [download] "You're only given one little spark of madness. You mustn't lose it." - Robin Williams	[reply] [d/l] [select]

Replies are listed 'Best First'.

Re^3: Learning about Arrays and Hashes - printing pieces of them
by NetWallah (Canon) on Jan 28, 2015 at 20:10 UTC

Just run you rprogam like this:

perl -d <Your-program-file-name>
[download]

Note: You need to FIRST use the "s" command to get the $rec variable initialized.

Here are the results of running your program - it includes answers to your questions:

  DB<1> s
main::(junk.pl:10):     print $rec->{TEXT},"\n",
main::(junk.pl:11):        $rec->{SEQUENCE}[0],"\n",
main::(junk.pl:12):      $rec->{LOOKUP}{"dog"},"\n";
  DB<1> x  $rec -> [Buick]
Not an ARRAY reference at (eval 7)[/usr/lib/perl5/5.10.0/perl5db.pl:63
+8] line 2.
  DB<2> x  $rec -> {LOOKUP} -> {cars}
0  'Buick'
  DB<3> x  $rec -> {LOOKUP} [0]
Not an ARRAY reference at (eval 9)[/usr/lib/perl5/5.10.0/perl5db.pl:63
+8] line 2.
  DB<4> x  $rec -> {LOOKUP} {dog}
0  'hound'
  DB<5> q
[download]

"You're only given one little spark of madness. You mustn't lose it." - Robin Williams

[reply]
[d/l]
[select]