How do I print a hash so that it represents actual table with column headers?

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Re: How do I print a hash so that it represents actual table with column headers? by Fastolfe (Vicar) on Nov 12, 2000 at 13:36 UTC
A hash only contains keys and values, so I'm not sure what sort of header you'd want. Perhaps printf can be of use: `printf "%20s %s\n", "Key", "Value"; printf "%20s-%s\n", "-"x20, "-----"; foreach my $key (keys %hash) { printf "%20s %s\n", $key, $hash{$key}; }` [download] If you're talking about a more complex data structure (such as a homogenous hash of hashes), perhaps something more like this would be to your liking: `# $hash{$key} = { field1 => 'value', ... }; my @keys = keys %{$hash{(keys %hash)[0]}}; my $format = "%10s " . ("%10s " x @keys) . "\n"; printf $format, "Key", @keys; foreach my $key (keys %hash) { printf $format, $key, @{$hash{$key}}{@keys}; }` [download]	[reply] [d/l] [select]
RE: Answer: How do I print a hash so that it represents actual table with column headers? by merlyn (Sage) on Nov 12, 2000 at 16:56 UTC
To get a slice from `%$hash` of keys `@keys`, use `@$hash{@keys}`, which can easily be derived from the more general form of `@{...HASHREF...}{...keys-in-list-context...}`. -- Randal L. Schwartz, Perl hacker	[reply]
Re: How do I print a hash so that it represents actual table with column headers? by toolic (Bishop) on Sep 01, 2009 at 01:51 UTC
Text::Table can be used to format the keys and values of a simple hash as a 2-column table. It automatically calculates the width of each column. `use Text::Table; my $tb = Text::Table->new(qw(Keys Values)); # column headers for my $k (keys %hash) { $tb->add($k, $hash{$k}) } print $tb;` [download]	[reply] [d/l]
Re: How do I print a hash so that it represents actual table with column headers? by CharlesClarkson (Curate) on Jun 11, 2001 at 13:33 UTC
In response to the note above: `my %tmp = %{$hash{$key}}; printf($format, $key, @tmp{@keys});` [download] Could be rewritten as: `printf($format, $key, @{$hash{$key}{@keys});` [download] Originally posted as a Categorized Answer.	[reply] [d/l] [select]