September 2012
Beginner
744 pages
15h 48m
English
Content preview from Beginning PerlBecome an O’Reilly member and get unlimited access to this title plus top books and audiobooks from O’Reilly and nearly 200 top publishers, thousands of courses curated by job role, 150+ live events each month,
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Chapter 5
Control Flow
WHAT YOU WILL LEARN IN THIS CHAPTER:
- Working with if/elsif/else expressions
- What are and when to use for/foreach loops
- Understanding and working with while/until loops
- Understanding the various statement modifiers and how to use do while/do until
- What are given/when statements and statement modifiers and when to use them
WROX.COM CODE DOWNLOADS FOR THIS CHAPTER
The wrox.com code downloads for this chapter are found at http://www.wrox.com/WileyCDA/WroxTitle/Beginning-Perl.productCd-1118013847,descCd-DOWNLOAD.html on the Download Code tab. The code for this chapter is divided into the following major examples:
- Example_5_1_unique.pl
- Example_5_2_arrays.pl
From previous chapters, you now understand some of the basics of Perl, but now you get closer to the heart of programming. When you program, you constantly make decisions loop over data based on those decisions. That’s what this chapter is all about: how Perl makes decisions and looping over data.
USING THE IF STATEMENT
This section starts with boolean logic. As explained in Chapter 4, the following values are considered “false” in Perl:
- undef
- "" (the empty string)
- 0
- 0.0
- "0" (the “string” zero)
Some languages have specific boolean objects, or TRUE and FALSE identifiers. Perl does things a little differently. As you work through the examples, try to see what Perl does and why. If you have experience with programming languages that have a different approach, consider the strengths and weaknesses of the different ...
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O’Reilly covers everything we've got, with content to help us build a world-class technology community, upgrade the capabilities and competencies of our teams, and improve overall team performance as well as their engagement.Julian F.
I wanted to learn C and C++, but it didn't click for me until I picked up an O'Reilly book. When I went on the O’Reilly platform, I was astonished to find all the books there, plus live events and sandboxes so you could play around with the technology.Addison B.
I’ve been on the O’Reilly platform for more than eight years. I use a couple of learning platforms, but I'm on O'Reilly more than anybody else. When you're there, you start learning. I'm never disappointed.Amir M.
I'm always learning. So when I got on to O'Reilly, I was like a kid in a candy store. There are playlists. There are answers. There's on-demand training. It's worth its weight in gold, in terms of what it allows me to do.