Array Declaring Convention

[litlmike]

Is there a "convention" for adding a column to a 1-D array? This is one of those answers that I should know, but I have been avoiding this one for awhile and just kept coming up with a work around for the particular situations. It is about time I address it. What is the proper way to accomplish this?

So if I had these as inputs:

Local $aArray1[3] = [1, 2, 3]

Local $aArray2[3] = ["A", "B", "C"]

And wanted this as the output:

Local $aArray1[3][2] = [[1,"A"],[2,"B"],[3,"C"]]

My guess is something like:

Local $aArray1[3] = [1, 2, 3]
Local $aArray2[3] = ["A", "B", "C"]

For #of Arrays
ReDim $aArray1[3][$i] = [ [ aArray1[$i], $aArray2[$i] ]

Next

[PsaltyDS]

Is there a "convention" for adding a column to a 1-D array? This is one of those answers that I should know, but I have been avoiding this one for awhile and just kept coming up with a work around for the particular situations. It is about time I address it. What is the proper way to accomplish this?

So if I had these as inputs:

Local $aArray1[3] = [1, 2, 3]

Local $aArray2[3] = ["A", "B", "C"]

And wanted this as the output:

Local $aArray1[3][2] = [[1,"A"],[2,"B"],[3,"C"]]

My guess is something like:

Local $aArray1[3] = [1, 2, 3]
Local $aArray2[3] = ["A", "B", "C"]

For #of Arrays
ReDim $aArray1[3][$i] = [ [ aArray1[$i], $aArray2[$i] ]

Next

Couple of problems:

1. You can't change the number of dimensions/indexes without losing the data.

2. You can't preset data with ReDim the way you can with Dim/Local/Global.

So in this case, you need to declare a new array, then use a loop to add all the data:

#include <Array.au3>

Global $aArray1[3] = [1, 2, 3]
Global $aArray2[3] = ["A", "B", "C"]

Global $aArray3[UBound($aArray1)][2]

For $row = 0 To UBound($aArray1) - 1 
    $aArray3[$row][0] = $aArray1[$row]
    $aArray3[$row][1] = $aArray2[$row]
Next

_ArrayDisplay($aArray3, "Result")

muttley

[litlmike]

Couple of problems:

1. You can't change the number of dimensions/indexes without losing the data.

2. You can't preset data with ReDim the way you can with Dim/Local/Global.

So in this case, you need to declare a new array, then use a loop to add all the data:

#include <Array.au3>

Global $aArray1[3] = [1, 2, 3]
Global $aArray2[3] = ["A", "B", "C"]

Global $aArray3[UBound($aArray1)][2]

For $row = 0 To UBound($aArray1) - 1 
    $aArray3[$row][0] = $aArray1[$row]
    $aArray3[$row][1] = $aArray2[$row]
Next

_ArrayDisplay($aArray3, "Result")

muttley

Thanks you kindly for clearing up the ReDim limitations and showing the convention here.

[litlmike]

One other question:

If I am going to use _ArrayAdd to fill an array, what is the best practice to declare the 'blank' array and fill it?

I have been using:

Local $aArray[1]=[""]

For $i=0 To 5
_ArrayAdd($aArray, $i)
Next

Then ending with either:

_ArrayDelete($aArray, 0)

or

$aArray[0]=Ubound($aArray)

[PsaltyDS]

One other question:

If I am going to use _ArrayAdd to fill an array, what is the best practice to declare the 'blank' array and fill it?

I have been using:

Local $aArray[1]=[""]

For $i=0 To 5
_ArrayAdd($aArray, $i)
Next

Then ending with either:

_ArrayDelete($aArray, 0)

or

$aArray[0]=Ubound($aArray)

You need to decide if you know what the first values should be when you declare it or must fill them in later, and if [0] will be used as a count or as a data element:

Local $aArray[6] = [0,1,2,3,4,5]; [0] = first data element

; - or - 

Local $aArray[6] = [5,1,2,3,4,5]; [0] = count

; - or - 

Local $aArray[1]; [0] = first data element
; ... filling in later:
Local $n = 5
ReDim $aArray[$n + 1]
For $i=0 To $n
     $aArray[$i] = $i
Next

; - or - 

Local $aArray[1]=[0]; [0] = count
For $i=1 To 5
_ArrayAdd($aArray, $i)
Next
$aArray[0] = Ubound($aArray) - 1

; ...etc., too many variations to list

muttley

[litlmike]

You need to decide if you know what the first values should be when you declare it or must fill them in later, and if [0] will be used as a count or as a data element:

Local $aArray[6] = [0,1,2,3,4,5]; [0] = first data element

; - or - 

Local $aArray[6] = [5,1,2,3,4,5]; [0] = count

; - or - 

Local $aArray[1]; [0] = first data element
; ... filling in later:
Local $n = 5
ReDim $aArray[$n + 1]
For $i=0 To $n
     $aArray[$i] = $i
Next

; - or - 

Local $aArray[1]=[0]; [0] = count
For $i=1 To 5
_ArrayAdd($aArray, $i)
Next
$aArray[0] = Ubound($aArray) - 1

; ...etc., too many variations to list

muttley

Ahhh, thanks. I like this, it is always good to know what conventions I should be using. So then, Local $aArray[1]=[0]; ending with $aArray[0] = Ubound($aArray) - 1, looks like the most reasonable method for most situations.

When you are in the middle of a script, how do you personally decide "if [0] ... should be used as a count or as a data element"?

[JFee]

Well it depends on your goal. If you are going to return the array from a function, I usually use [0] as a count. Other times... I still start at [1] for my data muttley

[PsaltyDS]

When you are in the middle of a script, how do you personally decide "if [0] ... should be used as a count or as a data element"?

That's a design decision you make to fit the situation at the time you are coding the script. If you need to use references to the count often, "$aArray[0]" might be cleaner than "Ubound($aArray) - 1". If your array will be passed to other functions as a parameter, then you go with whatever those functions expect.

Just go with what makes sense at the time, and note your decision for future reference by a comment where you declare the array!

muttley