2D arrays compare with details - yet another solution

[jchd]

Yes guinness, that and the fact that in this case IsArray and UBound give seemingly contradictory results. But again those truly empty arrays are rare objects.They could be put at work in a good number of situations but producing one isn't native.

Another (better in my view) serious candidate result for failure is the new keyword Null but it's generalization would break too much code that it will have to wait forever AutoIt v4.

[czardas]

I'm not quite following this. If an array can potentially have 0 dimensions (whatever that might mean) then the apparently contradictory results from IsArray and Ubound both ought to be correct. So why would Ubound be better suited to test the data type? Surely it would be the opposite - in that it may return zero for a true case - and the only way to be certain is to check if an error was also returned. Now I don't know how I could use an array with zero dimensions, but if such a beast exists for a reason, then the faster IsArray ought to give you the data type without any additional checks being required. Maybe I'm missing something - and I don't know how to test it.

I think I should add that I like orbs' idea and sorry for going off topic.

Edited June 6, 2013 by czardas

[jchd]

Because native AutoIt arrays must have at least one element in some dimension, contrary to possibly empty COM-generated arrays.

If you test with IsArray, then you (sometimes, depending on context) will have to test for UBound as well because if you don't and happen to act on an empty array, then any index you use will cause the interpretor to raise the final red flag.

From this point of view, UBound never lies.

For a more in depth discussion of empty arrays, read from >this thread.

[guinness]

For a more in depth discussion of empty arrays, read from >this thread.

They can't as it's in the MVP Forum.

[FireFox]

Strictly speaking, an empty array is not at all obvious to build with AutoIt alone. AFAIK only [some?] objects may return empty arrays. In this case IsArray is True but dimensions are 0. There has been a thread about this, with trancexx posting there.

Like this ?

Local $a = StringSplit("", "", 2)
 
ConsoleWrite(UBound($a) & @CrLF)
ConsoleWrite(IsArray($a) & @crlf)

[guinness]

 

Like this ?

Local $a = StringSplit("", "", 2)
 
ConsoleWrite(UBound($a) & @CrLF)
ConsoleWrite(IsArray($a) & @crlf)

Similar, yes.

[jchd]

My bad, you're right guinness. So mere humans, read about empty arrays what's written on this topic in your nearest black hole (no pun intended).

[czardas]

LOL you guys crack me up. Arrays get squashed into zero dimensions inside black holes. I never use IsArray, because I know if it is intuitively.

If you test with IsArray, then you (sometimes, depending on context) will have to test for UBound as well because if you don't and happen to act on an empty array, then any index you use will cause the interpretor to raise the final red flag.

 

From this point of view, UBound never lies.

 

This for example would be a valid exception.

Local $vReturnValue = 0 ; Could be an array

If IsArray($vReturnValue) Then
    ReDim $vReturnValue[1] ; We don't care about Ubound
Else
    ; Do something else
EndIf