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Apr 18, 2002, 5:46 AM
yogi
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Apr 18, 2002, 5:46 AM
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map
Hi everyone,

I want to learn how to use the map function. I have a little example where I think it could be used,
Code:
foreach (keys %$link) {
$tags->{"links_link_$_"} = $link->{$_}
};
This takes the hashref $links = { key => value} and maps it to $tags = { links_link_key => value}.

How would I do that using map? I tried, but obviously failed (otherwise I wouldn't be asking....)

Ivan
-----
Iyengar Yoga Resources / GT Plugins
Apr 18, 2002, 5:52 AM
Paul
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Apr 18, 2002, 5:52 AM
Post #2 of 10
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Re: [yogi] map In reply to
Hi,

What did you try?

Something like this should work:
Code:
my %$tags = map { "links_link_$_" => $link->{$_} } keys %$link;

Last edited by:

Paul: Apr 18, 2002, 6:14 AM
Apr 18, 2002, 5:55 AM
yogi
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Apr 18, 2002, 5:55 AM
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Re: [Paul] map In reply to
That's exacly what I tried, but it gives me a syntax error...

Ivan
-----
Iyengar Yoga Resources / GT Plugins
Apr 18, 2002, 5:56 AM
Paul
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Apr 18, 2002, 5:56 AM
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Re: [yogi] map In reply to
Are you sure you didn't insert a comma after } by accident?...I sometimes do that.

Last edited by:

Paul: Apr 18, 2002, 5:57 AM
Apr 18, 2002, 5:58 AM
yogi
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Apr 18, 2002, 5:58 AM
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Re: [Paul] map In reply to
Yes, very sure. I tried that too...

Ivan
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Iyengar Yoga Resources / GT Plugins
Apr 18, 2002, 6:03 AM
Paul
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Apr 18, 2002, 6:03 AM
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Paul: Apr 18, 2002, 6:04 AM
Apr 18, 2002, 6:05 AM
Paul
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Apr 18, 2002, 6:05 AM
Post #7 of 10
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Re: [yogi] map In reply to
Ok, the following works:

Code:
my %$tags = map { $_ => $link->{$_} } keys %$link;

...but this doesn't:

Code:
my %$tags = map { "links_link_$_" => $link->{$_} } keys %$link;

So it seems it has a problem with the key. Hmm Im gonna have a play about...
Apr 18, 2002, 6:08 AM
yogi
Veteran (2199 posts)
Apr 18, 2002, 6:08 AM
Post #8 of 10
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Re: [Paul] map In reply to
I just found out that the following works (strangely enough):
Code:
my %$tags = map { 'links_link_' . $_ => $link->{$_} } keys %$link;

Thanks for your help anyway.

Ivan
-----
Iyengar Yoga Resources / GT Plugins

Last edited by:

yogi: Apr 18, 2002, 6:11 AM
Apr 18, 2002, 6:10 AM
Paul
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Apr 18, 2002, 6:10 AM
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Re: [yogi] map In reply to
Ok here ya go :)

Code:
my %$tags = map { eval { qq{links_link_$_} } => $link->{$_} } keys %$link;
Jul 24, 2002, 4:27 AM
Paul
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Jul 24, 2002, 4:27 AM
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Re: [yogi] map In reply to
Hehe the answer to this question was so easy yet at the time I just totally didn't know what I was on about :)

Quote:
my %$tags = map { "links_link_$_" => $link->{$_} } keys %$link;

That's exacly what I tried, but it gives me a syntax error...

It is because perl is trying to evaluate the code as an expression rather than a block, changing it to:

my %$tags = map { +"links_link_$_" => $link->{$_} } keys %$link;

...will get rid of the error :)