Quickly determine if a varable is an array and get dimensions

[darrellblackhawk]

[tt]

CLEAR

LOCAL i

LOCAL ARRAY a1[1], a2[1,2], a3[2,1], a4[4,3], a5[43,53]

? IsArray(@i)
? IsArray(@a1)
? IsArray(@a2)
? IsArray(@a3)
? IsArray(@a4)
? IsArray(@a5)

* Results at runtime: (added star)
*0'
*1,1,1
*1,1,2
*1,2,1
*1,4,3
*1,43,53



* Pass the variable by reference to determine if it's an
* array. If it is, return a comma delimited string,
* otherwise returns "0"

FUNCTION IsArray(aSuspect)
RETURN IIF(TYPE(&quot;aSuspect[1]&quot<>&quot;U&quot;,&quot;1,&quot; + ;
TRANSFORM(ALEN(aSuspect,1)) + &quot;,&quot; + ;
TRANSFORM(INT(ALEN(aSuspect)/ALEN(aSuspect,1))),&quot;0&quot
ENDFUNC
[/tt]

Darrell

 

[Mike Gagnon]

Doesn't an Array return VARTYPE = &quot;A&quot; (OR TYPE)?

Mike Gagnon

If you want to get the best response to a question, please check out FAQ184-2483 first.

 

[darrellblackhawk]

I'm using VFP6.0 still.

Darrell

 

[DSummZZZ]

Mike,

If you use VARTYPE() or TYPE() on an array, they return the variable type of the first element of that array.
At least up to VFP 7. I haven't used VFP 8 yet, it could have changed.


-Dave S.-

Even more Fox stuff at:

http://www.davesummers.net/foxprolinks.htm

 

[darrellblackhawk]

The purpose of the function is to determine if a
variable passed in by 'reference' is an array, plus
to determine its dimensions if it is an array.

I believe in VFP 8; as Mike posted; VFP returns
'A' for array types.

Darrell

 

[Dan Freeman]

In *all* versions of VFP, test the type of the first element:

If Type('lalArray[1]') # &quot;U&quot;
* You've got an array
Endif

If the first element is undefined (Type() = &quot;U&quot, you don't have an array.

 

[DSummZZZ]

danfreeman,

But if the variable is not an array, you will get an error.


-Dave S.-

Even more Fox stuff at:

http://www.davesummers.net/foxprolinks.htm

 

[craigsboyd]

Dave,

Are you sure about that? Tested ok for me.

Slighthaze = NULL
_{craig1442@mchsi.com}

&quot;Whom computers would destroy, they must first drive mad.&quot; - Anon​

 

[DSummZZZ]

Hmm. Not sure what Iwas doing, but I must have been using just VARTYPE() to test. But after doing the following, the tested the same using TYPE() and VARTYPE():

DIMENSION zzz[3]
?Vartype(zzz)    &&... returns 'L'
?Vartype(zzz[1]) &&... returns 'L'

zzz[1] = 'A'
zzz[2] = 1
zzz[3] = .T.
?Vartype(zzz)    &&... returns 'C'
?Vartype(zzz[1]) &&... returns 'C'
?Vartype(zzz[2]) &&... returns 'N'
?Vartype(zzz[3]) &&... returns 'L'

But, using VARTYPE() and TYPE() here:

STORE 'A' TO yyy
?Vartype(yyy)    &&... returns 'C'
?Vartype(yyy[1]) &&... File 'yyy.prg' does not exist

STORE 'A' TO yyy
?Type('yyy')    &&... returns 'C'
?Type('yyy[1]') &&... returns 'U'

It looks like TYPE() works as noted.
Let's go with that.


-Dave S.-

Even more Fox stuff at:

http://www.davesummers.net/foxprolinks.htm