# Question on Arrays (beginner)

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Hi I have a question regarding arrays as I'm still trying to grasp the concept.

Over at http://www.autoitscript.com/wiki/Arrays, it states you have to do a -1 to get the actual index (since computer counts starting at 0)

So its example:

```Local \$arr[3] = ["element 1", "element 2", "element 3"]

For \$i = 0 to 3 - 1 ; We have an array with three elements but the last index is two.
ConsoleWrite(\$arr[\$i] & @LF)
Next```

My question is, why wouldn't you just change "For \$i = 0 to 3 -1" to "For \$i = 0 to 2"?

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My question is, why wouldn't you just change "For \$i = 0 to 3 -1" to "For \$i = 0 to 2"?

Well you could if you wanted. With larger arrays though, it's easier to use UBound -1, or just UBound if that's the case.

Edited by somdcomputerguy

- Bruce /*somdcomputerguy */  If you change the way you look at things, the things you look at change.

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jgq85,

If you already know the size of the array, then of course you can use the actual value for the top index:

```Local \$arr[3] = ["element 1", "element 2", "element 3"]
For \$i = 0 to 2                                            ; You can use the actual value here
ConsoleWrite(\$arr[\$i] & @LF)
Next```
But if you have an array of unknown size (after using FileReadToArray for example) you need to do as somdcomputerguy suggested - use UBound and subtract 1 to get the top index:

```Local \$aLines = FileReadToArray("File_Path")
For \$i = 0 to UBound(\$aLines) - 1                          ; But here you need to calculate the top index
ConsoleWrite(\$arr[\$i] & @LF)
Next```
Just so you know, in the new Beta you get the number of lines read returned in @extended so you could use that instead.

M23

Any of my own code posted anywhere on the forum is available for use by others without any restriction of any kind

Open spoiler to see my UDFs:

Spoiler

ArrayMultiColSort ---- Sort arrays on multiple columns
ChooseFileFolder ---- Single and multiple selections from specified path treeview listing
Date_Time_Convert -- Easily convert date/time formats, including the language used
ExtMsgBox --------- A highly customisable replacement for MsgBox
GUIExtender -------- Extend and retract multiple sections within a GUI
GUIFrame ---------- Subdivide GUIs into many adjustable frames
GUIListViewEx ------- Insert, delete, move, drag, sort, edit and colour ListView items
GUITreeViewEx ------ Check/clear parent and child checkboxes in a TreeView
Marquee ----------- Scrolling tickertape GUIs
NoFocusLines ------- Remove the dotted focus lines from buttons, sliders, radios and checkboxes
Notify ------------- Small notifications on the edge of the display
Scrollbars ----------Automatically sized scrollbars with a single command
StringSize ---------- Automatically size controls to fit text
Toast -------------- Small GUIs which pop out of the notification area

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