### How do I take a slice of a hash reference?

by entropy (Sexton)
 on May 15, 2001 at 03:17 UTC Need Help??
Contributed by entropy on May 15, 2001 at 03:17 UTC
Q&A  > references

#### Description:

I can take a slice of an array ref, but not of a hash ref:
```my \$arr =[1,'a',2,'b'];
my \$hash={1,'a',2,'b'};
print join ':',(@\$arr )[1,2];
print join ':',(@\$hash){1,2};
The first print statement works, the second is a syntax error. I also have this problem when taking a slice of an anonymous hash:
```print join ':',(1,'a',2,'b')[1,2];
print join ':',(1,'a',2,'b'){1,2};
Again, the first statement works, but the second is a syntax error.

 Answer: How do I take a slice of a hash reference?contributed by japhy Here's how: ```@slice = @{\$array_ref}[ @idx ]; @slice = @{\$hash_ref}{ @keys }; [download]``` And there's no easy way to "pretend" a list is a hash. You need to use a hash reference explicitly: ```\$scalar = {1, 'a', 2, 'b'}->{\$key}; @slice = @{ { 1, 'a', 2, 'b' } }{ @keys }; [download]``` Answer: How do I take a slice of a hash reference?contributed by tianping japhy has answered the question, but it's also worth pointing out the solution to the syntax error in your original code. The parentheses alter the priority; so just remove them: ```print join ':', @\$hash{1,2}; [download]``` More generally, put curly braces around the hash ref expression: ```print join ':', @{\$hash}{1,2}; [download]```

• Posts are HTML formatted. Put <p> </p> tags around your paragraphs. Put <code> </code> tags around your code and data!
• Titles consisting of a single word are discouraged, and in most cases are disallowed outright.
• Read Where should I post X? if you're not absolutely sure you're posting in the right place.
• Posts may use any of the Perl Monks Approved HTML tags:
a, abbr, b, big, blockquote, br, caption, center, col, colgroup, dd, del, div, dl, dt, em, font, h1, h2, h3, h4, h5, h6, hr, i, ins, li, ol, p, pre, readmore, small, span, spoiler, strike, strong, sub, sup, table, tbody, td, tfoot, th, thead, tr, tt, u, ul, wbr
• You may need to use entities for some characters, as follows. (Exception: Within code tags, you can put the characters literally.)
 For: Use: & & < < > > [ [ ] ]
• Link using PerlMonks shortcuts! What shortcuts can I use for linking?

Create A New User
Chatterbox?
 [jedikaiti]: Good \$localtime, Monks

How do I use this? | Other CB clients
Other Users?
Others chilling in the Monastery: (12)
As of 2017-07-20 15:49 GMT
Sections?
Information?
Find Nodes?
Leftovers?
Voting Booth?
I came, I saw, I ...

Results (305 votes). Check out past polls.