Coding 101 21: Perl: Getting Started

Hosts: Fr. Robert Ballecer, SJ and Shannon Morse

Guest: Patrick Delahanty

Ivory Tower

Control Structures
* The structure of Perl is more like C# than Python
-- While Python uses whitespace 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 seperately from expressions.
* You can declare variable WITHIN the expression.

Perl offers three types of variables: Scalars, Arays 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 differerentiate between integers and real numbers

Usage of Scalars:
* You declare a scalar variable by using "$" right befofe the name of the variable
$Var1 = 28 Creates a variable named "Var1" containing the integer "4"
$Var2 = "Coding 101" Crates 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"

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Running time: 42:03