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Is it taboo to have a variable be declared twice?

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I have Opt('MustDeclareVars', 1) turned on for good practice, and I was wondering if it is bad practice to allow a variable to be "declared" (like Local $var) multiple times as the sript runs through it's While loop.

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If I correctly remember a Dev's answer to a previous question like this, you slow down the loop if you declare the variable each time you pass through it as AutoIt has to check if the variable has already been declared on every pass. So better practice would be to do as Deathbringer suggested and declare it the once before the loop starts. :P

If you declare a variable within a single conditional statement, you should always declare it first, as if the condition is not met you will not run the line of code containing the variable declaration and thus are very likely to get an error. :x If there are multiple conditions I tend to declare the most likely value of the variable first and then change it if needed - something like this:

; Rather than this:
If $fFlag = True Then
   Local $vVar = 1
   Local $vVar = 2

; I do this
Local $vVar = 2
If $fFlag = True Then $vVar = 1

Then the variable is always declared - and AutoIt may have fewer conditions to evaluate. :shifty:


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


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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As Deathbringer mentioned I always use #AutoIt3Wrapper_Au3Check_Parameters=-q -d -w 1 -w 2 -w 3 -w 4 -w 5 -w 6 and this has helped me understand declaration of variables a lot better, but didn't realise that declaring a variable in a loop could cause the loop to slow down.

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Updated: 04/09/2015

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