Coding 101 21: Perl: Getting Started

Ivory Tower

Control Structures

The structure of Perl is more like C# than Python
While Python uses white-space to delineate lines of code, Perl uses ";" a semicolon
Also like C#, Perl uses "{}" Curly brackets to create BLOCKS of code Variables
Much like Python, Perl doesn't require you to declare variables separately from expressions.
You can declare variable WITHIN the expression.
Perl offers three types of variables: Scalars, Arrays and Associative Arrays
We're going to show you the first two: Scalars and Arrays

Printing in Perl

Printing in Perl works much in the same way as printing in Python
You can print numbers, strings, variables, and combinations thereof.

Scalars

These are either numbers or strings
Perl doesn't require you to mark a variable as either a number or a string... it all looks the same to Perl
Perl also doesn't require you to differentiate between integers and real numbers

Usage of Scalars:

You declare a scalar variable by using "$" right before the name of the variable
$Var1 = 28 creates a variable named "Var1" containing the integer "4"
$Var2 = "Coding 101" creates a variable named "Var2" containing the string "Coding 101"
$Var3 = 3.14 creates a variable named "Var3" containing the decimal number "4.5"

Arrays

An array is a ONE-DIMENSIONAL indexed list of Scalar variables

Usage of Arrays

You declare an array by using "@" right before the name of the array
Individual scalar variables within the array can be accessed by pointing to their index with the SCALAR identifier
@C101 = ("Padre", "Snubs", "Bryan") creates an array named "C101" and fills it with the strings, "Padre", "Snubs" and "Bryan"
@coding = @C101 creates an array called, "coding" and fills it with the values from the array "C101"
$C101[2] = "Cranky Hippo" changes the value in the third item in the array "C101" from "Bryan" to "Cranky Hippo"

Hosts: Fr. Robert Ballecer, SJ and Shannon Morse

Guest: Patrick Delahanty

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