I’ve been\u00a0 hearing about hashtags for a few years now.\u00a0 At first, I wondered why people were suddenly showing much interest in data structures.<\/p>\n
A data structure is a way of storing data that suggests relationships between the entries.\u00a0 An array is a data structure:\u00a0 it stores a list of elements such that each has a position (or index) as well as a value.<\/p>\n
In comp sci, another term for hash<\/strong> is associative array<\/strong>.\u00a0 A hash stores values not by position, but by descriptor<\/strong>, also called key<\/strong>.<\/p>\n In Perl, the hash symbol is %.\u00a0 Here’s a short Perl program to illustrate a hash:<\/p>\n The program should politely ask you which Maritime province’s capital you want to know. Let’s imagine you key in NS. Hopefully, you’ll receive the reply<\/p>\n The captial of NS is Halifax.<\/span><\/p>\n There is much more to say about this topic. Look for more here soon.<\/p>\n HTH:)<\/p>\n Sources:<\/p>\n Robert’s Perl tutorial<\/a><\/p>\n McGrath, Mike. Perl in easy steps<\/em>. Southam: Computer Step, 2004.<\/p>\n
\n#!\/usr\/bin\/perl
\n
\n%maritimecapitals=(‘NB’,’Fredericton’,’NS’,’Halifax’,’PEI’,’Charlottetown’);
\n
\nprint “Hello. Which Maritime capital would you like to know?\\n\\n”;
\nprint “Key in NS for Nova Scotia, NB for New Brunswick, or\\n\\n”;
\nprint “PEI for Prince Edward Island.\\n\\n”;
\n$prov=<STDIN>;
\nchomp $prov;
\nprint “The capital of $prov is $maritimecapitals{$prov}.\\n\\n”;
\n<\/span>
\nLet’s imagine you call this program maricaps.txt<\/span>, then, from its directory, you key in
\nperl maricaps.txt<\/span><\/p>\n