Coding 101

Jun 12th 2014

Coding 101 21

Perl: Getting Started

Perl installation.
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Category: Help & How To

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"

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