Solved

Simple question about associative arrays in Perl

Posted on 2001-07-01
2
328 Views
Last Modified: 2008-03-10
I have been learning Perl from a book called "Perl in Examples" and there within is a segment about associative arrays (hashes) that kind of breezes over the how it worx..and basically gives a little example of what to type and what will happen. Here is the code:
%associativeArray = ("Jack A.", "Dec 2", "Joe B.", "June 2", "Jane C.", "Feb 13");
$associativeArray{"Jennifer S."} = "Mar 20";
print "Joe's birthday is: " . $associativeArray{"Joe B."} . "\n";
print "Jennifer's birthday is: " . $associativeArray{"Jennifer S."} . "\n";

This program will print the following:

Joe's birthday is: June 2
Jennifer's birthday is: Mar 20

....all of this seems fine and dandy and I've tried it and it worx fine..and i can see how perl came upon Jennifer's birthday..what i don't understand is how it decided that Joe's birthday would b June 2..does it just associate "Joe B." with "June 2" becuz "Joe B." precedes "June 2"?
..umm i think that makes sense..i would really appreciate any help u have to offer!                                          


0
Comment
Question by:JohnBlazes
[X]
Welcome to Experts Exchange

Add your voice to the tech community where 5M+ people just like you are talking about what matters.

  • Help others & share knowledge
  • Earn cash & points
  • Learn & ask questions
2 Comments
 
LVL 8

Expert Comment

by:mnashadka
ID: 6246536
If you initialize an associative array that way, it will make every odd value a key and every even value the corresponding value.  i.e. Jack A. would correspond with Dec 2, Joe B. with June 2, etc.  It's a very powerful feature, but I think that maybe perl allows you to use the associative array too many ways, but I'm sure that others would disagree.
0
 

Accepted Solution

by:
wkmatt42 earned 50 total points
ID: 6246541
A better way to write the same thing is:

%associativeArray =
("Jack A." => "Dec 2",
 "Joe B." => "June 2",
 "Jane C." => "Feb 13");

You were correct in your assumption about how the items were reletated: 2 is associated with 1, 4 with 3, etc. The notation above makes that a little more obvious, so I'm surprised your book didn't opt for it.

You'll probably see the term "hash" used more often than "associate array" to refer to the same thing.

Since you're new to Perl, I'd recommend picking up "Programming Perl" by Larry Wall, etc. There's a companion "Learning Perl" which is nice too, but your bookshelf won't be complete without "Programming Perl".


0

Featured Post

On Demand Webinar - Networking for the Cloud Era

This webinar discusses:
-Common barriers companies experience when moving to the cloud
-How SD-WAN changes the way we look at networks
-Best practices customers should employ moving forward with cloud migration
-What happens behind the scenes of SteelConnect’s one-click button

Question has a verified solution.

If you are experiencing a similar issue, please ask a related question

Suggested Solutions

Title # Comments Views Activity
Problem to command 8 100
what is Amazon Linux AMI 6 74
how can i fully uninstall a puppet client? 2 113
awk file 6 99
Have you ever been frustrated by having to click seven times in order to retrieve a small bit of information from the web, always the same seven clicks, scrolling down and down until you reach your target? When you know the benefits of the command l…
The purpose of this article is to fix the unknown display problem in Linux Mint operating system. After installing the OS if you see Display monitor is not recognized then we can install "MESA" utilities to fix this problem or we can install additio…
In a recent question (https://www.experts-exchange.com/questions/29004105/Run-AutoHotkey-script-directly-from-Notepad.html) here at Experts Exchange, a member asked how to run an AutoHotkey script (.AHK) directly from Notepad++ (aka NPP). This video…
In an interesting question (https://www.experts-exchange.com/questions/29008360/) here at Experts Exchange, a member asked how to split a single image into multiple images. The primary usage for this is to place many photographs on a flatbed scanner…

756 members asked questions and received personalized solutions in the past 7 days.

Join the community of 500,000 technology professionals and ask your questions.

Join & Ask a Question