Hello Guys! I wanted to share all my knowledge on arrays! Hope may enjoy the article , Lets start!
Declaring arrays!
Declaring arrays is a little different than other variables:
; Rules to follow while declaring arrays:
;
; Rule #1: You must have a declarative keyword like Dim/Global/Local before the declaration unless the array is assigned a value from a functions return (Ex: StringSplit)
; Rule #2: You must declare the number of dimensions but not necessarily the size of the dimension if you are gonna assign the values at the time of declaration.
#include <Array.au3>
Local $aEmptyArray[0] ; Creates an Array with 0 elements (aka an Empty Array).
Local $aArrayWithData[1] = ["Data"]
_ArrayDisplay($aEmptyArray)
_ArrayDisplay($aArrayWithData)
That's it
Resizing Arrays
Its easy! Just like declaring an empty array! ReDim is our friend here:
#include <Array.au3>
Local $aArrayWithData[1] = ["Data1"]
ReDim $aArrayWithData[2] ; Change the number of elements in the array, I have added an extra element!
$aArrayWithData[1] = "Data2"
_ArrayDisplay($aArrayWithData)
Just make sure that you don't use ReDim too often (especially don't use it in loops!), it can slow down you program.
Best practice of using "Enum"
You might be wondering what they might be... Do you know the Const keyword which you use after Global/Local keyword? Global/Local are declarative keywords which are used to declare variables, of course, you would know that already by now , If you check the documentation for Global/Local there is a optional parameter called Const which willl allow you to "create a constant rather than a variable"... Enum is similar to Const, it declares Integers (ONLY Integers):
Global Enum $ZERO, $ONE, $TWO, $THREE, $FOUR, $FIVE, $SIX, $SEVEN, $EIGHT, $NINE ; And so on...
; $ZERO will evaluate to 0
; $ONE will evaluate to 1
; You get the idea :P
; Enum is very useful to declare Constants each containing a number (starting from 0)
This script will demonstrate the usefulness and neatness of Enums :
; We will create an array which will contain details of the OS
Global Enum $ARCH, $TYPE, $LANG, $VERSION, $BUILD, $SERVICE_PACK
Global $aOS[6] = [@OSArch, @OSType, @OSLang, @OSVersion, @OSBuild, @OSServicePack]
; Now, if you want to access anything related to the OS, you would do this:
ConsoleWrite(@CRLF)
ConsoleWrite('+>' & "Architecture: " & $aOS[$ARCH] & @CRLF)
ConsoleWrite('+>' & "Type: " & $aOS[$TYPE] & @CRLF)
ConsoleWrite('+>' & "Langauge: " & $aOS[$LANG] & @CRLF)
ConsoleWrite('+>' & "Version: " & $aOS[$VERSION] & @CRLF)
ConsoleWrite('+>' & "Build: " & $aOS[$BUILD] & @CRLF)
ConsoleWrite('+>' & "Service Pack: " & $aOS[$SERVICE_PACK] & @CRLF)
ConsoleWrite(@CRLF)
; Isn't it cool? XD
You can use this in your UDF(s) or Program(s), it will look very neat!
Looping through an Array
Looping through an array is very easy! . There are 2 ways to loop an array in AutoIt!
Simple Way:
; This is a very basic way to loop through an array
; In this way we use a For...In...Next Loop!
Global $aArray[2] = ["Foo", "Bar"] ; Create an array
; This loop will loop 2 times because our $aArray contains 2 elements.
For $vElement In $aArray ; $vElement will contain the value of the elements in the $aArray... one element at a time.
ConsoleWrite($vElement & @CRLF) ; Prints the element out to the console
Next
; And that's it!
Advanced Way:
; This is an advanced way to loop through an array
; In this way we use a For...To...Next Loop!
Global $aArray[4] = ["Foo", "Bar", "Baz", "Quack"] ; Create an array
; This loop will loop 2 times because our $aArray contains 2 elements.
For $i = 0 To UBound($aArray) - 1 ; $i is automatically created and is set to zero, UBound($aArray) returns the no. of elements in the $aArray.
ConsoleWrite($aArray[$i] & @CRLF) ; Prints the element out to the console.
Next ; This is the advanced way, we use $i to access the elements!
; With the advanced method you can also use the Step keyword to increase the offset in each "step" of the loop:
; This will only print every 2nd element starting from 0
ConsoleWrite(@CRLF & "Every 2nd element: " & @CRLF)
For $i = 0 To UBound($aArray) - 1 Step 2
ConsoleWrite($aArray[$i] & @CRLF)
Next
; This will print the elements in reverse order!
ConsoleWrite(@CRLF & "In reverse: " & @CRLF)
For $i = UBound($aArray) - 1 To 0 Step -1
ConsoleWrite($aArray[$i] & @CRLF)
Next
; And that ends this section!
For some reason, many people use the advance way more than the simple way . For more examples of loops see this post by @FrancescoDiMuro!
Interpreting Multi-Dimensional Arrays
Yeah, its the most brain squeezing problem for newbies, Imagining an 3D Array... I will explain it in a very simple way for ya, so stop straining you brain now! . This way will work for any array regardless of its dimensions...
Ok, Lets start... You can imagine an array as a (data) mine of information:
; Note that:
; Dimension = Level (except the ground level :P)
; Element in a Dimension = Path
; Level 2 ----------\
; Level 1 -------\ |
; Level 0 ----\ | |
; v v v
Local $aArray[2][2][2]
; \-----/
; |
; v
; Ground Level
; As you can see that $aArray is the Ground Level
; All the elements start after the ground level, i.e from level 0
; Level 0 Contains 2 different paths
; Level 1 Contains 4 different paths
; Level 2 Contains 8 different paths
; When you want too fill some data in the data mine,
; You can do that like this:
$aArray[0][0][0] = 1
$aArray[0][0][1] = 2
$aArray[0][1][0] = 3
$aArray[0][1][1] = 4
$aArray[1][0][0] = 5
$aArray[1][0][1] = 6
$aArray[1][1][0] = 7
$aArray[1][1][1] = 8
; Don't get confused with the 0s & 1s, Its just tracing the path!
; Try to trace the path of a number with the help of the image! Its super easy! :D
I hope you might have understand how an array looks, Mapping your way through is the key in Multi-Dimensional arrays, You take the help of notepad if you want! Don't be shy!
Frequently Asked Questions (FAQs) & Their answers
Q #1. What are Arrays?
A. An Array is an datatype of an variable (AutoIt has many datatypes of variables like "strings", "integers" etc. Array is one of them). An Array can store information in a orderly manner. An Array consist of elements, each element can be considered as a variable (and yes, each element has its own datatype!). AutoIt can handle 16,777,216 elements in an Array, If you have an Array with 16,777,217 elements then AutoIt crashes.
Q #2. Help! I get an error while declaring an Array!?
A. You tried to declare an array like this:
$aArray[1] = ["Data"]
That is not the right way, Array is a special datatype, since its elements can be considered as individual variables you must have an declarative keyword like Dim/Global/Local before the declaration, So this would work:
Local $aArray[1] = ["Data"]
Q #3. How can I calculate the no. of elements in an array?
A. The UBound function is your answer, Its what exactly does! If you have an multi-dimensional Array you can calculate the total no. of elements in that dimension by specifying the dimension in the second parameter of UBound
Q #4. Why is my For...Next loop throwing an error while processing an Array?
A. You might have done something like this:
#include <MsgBoxConstants.au3>
Local $aArray[10] = [1, 2, 3, 4, 5, 6, 7, 8, 9, 10]
Local $iMyNumber = 0
For $i = 0 To UBound($aArray) ; Concentrate here!
$iMyNumber += $aArray[$i]
Next
MsgBox($MB_OK, "Sum of all Numbers!", $iMyNumber)
Did you notice the mistake? UBound returns the no. of elements in an array with the index starting from 1! That's right, you need to remove 1 from the total no. of elements in order to process the array because the index of an array starts with 0! So append a simple - 1 to the statment:
#include <MsgBoxConstants.au3>
Local $aArray[10] = [1, 2, 3, 4, 5, 6, 7, 8, 9, 10]
Local $iMyNumber = 0
For $i = 0 To UBound($aArray) - 1
$iMyNumber += $aArray[$i]
Next
MsgBox($MB_OK, "Sum of all Numbers!", $iMyNumber)
Q #5. Can an Array contain an Array? How do I access an Array within an Array?
A. Yes! It is possible that an Array can contain another Array! Here is an example of an Array within an Array:
; An Array can contain another Array in one of its elements
; Let me show you an example of what I mean ;)
#include <Array.au3>
Global $aArray[2]
$aArray[0] = "Foo"
Global $aChildArray[1] = ["Bar"]
$aArray[1] = $aChildArray
_ArrayDisplay($aArray) ; Did you see that!? The 2nd element is an {Array} :O
; But how do we access it???
; You almost guessed it, like this:
; Just envolope the element which contains the {Array} (as shown in _ArrayDisplay) with brackets (or parentheses)! :D
ConsoleWrite(($aArray[1])[0]) ; NOTE the brackets () around $aArray[1]!!! They are required or you would get an syntax error!
; So this: $aArray[1][0] wont work!
More FAQs coming soon!
By PuneetTewani
By simonc8
By gahhon
