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"Or more simply as:" I would say that is debatable.

I think that sometimes we get a bit carried away with the "zoom" of Perl and don't emphasize the basics for beginners, i.e. we would do well to consider the audience when suggesting code.

The OP is a biologist, not a SW person. The purpose of my post was to show code that only used the most basic parts of beginning Perl - something simple - both from the program logic and the syntax. Also, this code may actually run faster than some some more terse versions!

For the OP, what jwkrahn is demonstrating here is called a "hash slice". This essentially combines multiple hash assignment statements, like: $hash{a}=0; $hash{b}=1; together as one statement, could be: @hash{'a','b'}=(0,1); This is great and cool stuff, but a plain old foreach() loop is just fine. Shorter code does not necessarily run faster - in fact, sometimes it runs slower, but it is sometimes easier to write for those "in the know". Perl is loaded with idioms. Extensive use of them is not necessary to write good solid, clear, high performing code.

The syntax for a hash slice looks similar to that of an array as a hash value. @{$hash{value}}, but it is not. The HoA (Hash of Array), @{$hash{value}} is the "take home", "use it often", "get used to seeing it" message here. A hash slice is less often encountered.

Anyway, my point here is that a hash slice is probably not "easier" for a beginner to understand because of the syntax.

In reply to Re^5: making presence/absence table from a hash of arrays by Marshall
in thread making presence/absence table from a hash of arrays by reubs85

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