Skip to Main Content
Learning Perl, 5th Edition
book

Learning Perl, 5th Edition

by Randal L. Schwartz, Tom Phoenix, brian d foy
June 2008
Beginner content levelBeginner
352 pages
11h 16m
English
O'Reilly Media, Inc.
Content preview from Learning Perl, 5th Edition

Chapter 2. Scalar Data

In English, as in many other spoken languages, you’re used to distinguishing between singular and plural. As a computer language designed by a human linguist, Perl is similar. As a general rule, when Perl has just one of something, that’s a scalar.[*] A scalar is the simplest kind of data that Perl manipulates. Most scalars are either a number (like 255 or 3.25e20) or a string of characters (like hello[] or the Gettysburg Address). Although you may think of numbers and strings as very different things, Perl uses them nearly interchangeably.

A scalar value can be acted upon with operators (like addition or concatenation), generally yielding a scalar result. A scalar value can be stored into a scalar variable. Scalars can be read from files and devices, and can be written out as well.

Numbers

Although a scalar is most often either a number or a string, it’s useful to look at numbers and strings separately for the moment. We’ll cover numbers first, and then move on to strings.

All Numbers Have the Same Format Internally

As you’ll see in the next few paragraphs, you can specify both integers (whole numbers, like 255 or 2001) and floating-point numbers (real numbers with decimal points, like 3.14159, or 1.35 × 1025). But internally, Perl computes with double-precision floating-point values.[*] This means that there are no integer values internal to Perl—an integer constant in the program is treated as the equivalent floating-point value.[] You probably won’t notice ...

Become 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,
and much more.
Start your free trial

You might also like

Learning Perl, 6th Edition

Learning Perl, 6th Edition

Randal L. Schwartz, brian d foy, Tom Phoenix
Beginning Perl

Beginning Perl

Curtis Ovid Poe
Learning Perl 6

Learning Perl 6

brian d foy
Mastering Perl

Mastering Perl

brian d foy

Publisher Resources

ISBN: 9780596520106Supplemental ContentErrata Page