comment on

<Updated>
I like nuance's idea (above). I now store undef as the value when a key is missing from one hash. See nuance's description above for an explanation of the "return" values.
</Updated>

Here's some punctuation for you:

(This is a short, concentrated way to do it - only 4 lines)

# Keys 7 and 8 are unique, keys 2,4 and 6 have different values
my %R = (1=>1, 2=>2,   3=>3, 4=>4,   5=>5, 6=>6,   7=>7);
my %S = (1=>1, 2=>'b', 3=>3, 4=>'d', 5=>5, 6=>'f', 8=>8);

# 1) Keys in %R which are not in %S
# 2) Keys in %S which are not in %R
# 3) Keys in both which have different values
my %Diffs = ((map(($_ => [$R{$_}, undef]),  grep {not exists $S{$_}} k
+eys %R)),
             (map(($_ => [undef,  $S{$_}]), grep {not exists $R{$_}} k
+eys %S)),
             (map(($_ => [$R{$_}, $S{$_}]),
                  grep {exists $S{$_} and $R{$_} ne $S{$_}}  keys %R))
+);

# Print out what we found
for (sort keys %Diffs){
  print $_, ': ', join(', ', map(defined $_ ? $_ : 'undef', @{$Diffs{$
+_}})), "\n";
}
[download]

A couple points to note:

if your values are numeric, change the 'ne' in the third Diffs section
we use an anonymous array ref to store the values in %Diffs, so remember to dereference it when you use %Diffs

Enjoy!

Russ

In reply to Re: diff of two hashes. by Russ
in thread diff of two hashes. by ChuckularOne

Are you posting in the right place? Check out Where do I post X? to know for sure.
Posts may use any of the Perl Monks Approved HTML tags. Currently these include the following:
<code> <a> <b> <big> <blockquote> <br /> <dd> <dl> <dt> <em> <font> <h1> <h2> <h3> <h4> <h5> <h6> <hr /> <i> <li> <nbsp> <ol> <p> <small> <strike> <strong> <sub> <sup> <table> <td> <th> <tr> <tt> <u> <ul>
Snippets of code should be wrapped in <code> tags not <pre> tags. In fact, <pre> tags should generally be avoided. If they must be used, extreme care should be taken to ensure that their contents do not have long lines (<70 chars), in order to prevent horizontal scrolling (and possible janitor intervention).
Want more info? How to link or How to display code and escape characters are good places to start.


Do you know where your variables are?
	PerlMonks