check blank logic field

[Thomas Holt]

Hello All,

Is there a way to check if there is a blank value in a logical field variable (i.e the field has had no data entered into it).

I guess this would be similar to :
var->character=" "
var->date={}

I have tried:
var->logical.T. .AND. var->logical.F.
Although this does not appear to work.

Any help with this as always greatly appreciated.

Cheers
Tom

[Stan Mathews]

RE: check blank logic field

I've tested isblank("logicalfieldname") and believe this works.

PS isblank() requires that the entry between the parentheses be inclosed with quotes.

[Stan Mathews]

RE: check blank logic field

Sorry, should be "enclosed with quotes".

[Tom Cone Jr]

RE: check blank logic field

As usual I agree with Stan.

I have a table called 'Mbrs'. It has a logical field called 'IsOk'. All the logical fields are blank...

If I open the table in the Interactive Editor, and interrogate it, here's what I see:


tbl = table.open("Mbrs")
? isblank("Mbrs->IsOk")
= .T.


? Mbrs->IsOk
= .F.


This shows that the logical value of a blank field is 'false', but also shows that you can use the isblank() function to identify logical fields which are blank...


Remembering to include the quotation marks around the fieldname is usually my downfall when using the isblank() function, so I'm glad Stan mentioned it, too.

[Thomas Holt]

RE: check blank logic field

Thanks Gentleman,

I have used :
isblank("quote->prem_fin")

And this now works a treat.
Is it down to my poor coding or is there a reason why that If I put that value into a variable called prem_depy I can't achieve the same result ??
Not a biggy as I now have what I need.

Many thanks for the quick and accurate responses.

Cheers
Tom

[Stan Mathews]

RE: check blank logic field

Thomas,

I dont know why it is designed that way, but the syntax for isblank() is

isblank(fieldnamestring).

This doesn't say that you can use a variable as the object of the function unless the variable contains a valid field name.

Stan

[Stan Mathews]

RE: check blank logic field

Thomas,

You might try this if you still need to use your variable.

dim your variable as logical (this assigns it a logical false value by default)

store your field value in the variable as you seem to indicate you were doing

now test the variable for !=.T. and !=.F.

If my thinking is correct, storing the field value to the variable should remove the default value. This is not tested, just an idea.

Stan