Instructing two way data exchange?

[Stan Mathews]

Re: Instructing two way data exchange?

Andy,

I agree with the other advice given but just to see how it would be done......

[Steve Andrews]

Re: Instructing two way data exchange?

This is what I had in mind for the most part.

[MoGrace]

Re: Instructing two way data exchange?

Hi Steve,
Could you please explain why this works?

tbl = table.current()
tbl.change_begin()
tbl.P1_set = (nLevel=1)
tbl.P2_set = (nLevel=2)
tbl.P3_set = (nLevel=3)
tbl.P4_set = (nLevel=4)
tbl.change_end()

Is (nlevel=1) returning a true/false statement? I have not seen this syntax before. It looks like a shortcut for a series of IF...THEN statements.

[Stan Mathews]

Re: Instructing two way data exchange?

Since nLevel is set elsewhere this is farily easily tested in the interactive.

nLevel = 1
?  (nLevel=1)
= .T.

? (nLevel=2)
= .F.

[MoGrace]

Re: Instructing two way data exchange?

Gee Stan, I guess I have never thought to use it that way! I guess if the IW produces something then it is valid to use elsewhere...

I feel so duh...dumb.

Just tried it myself - the IW didn't need the brackets. I assume the script does because of the = sign in the script. So the brackets are just denoting a formula else it would cause an error. Funny how you can know something in one context and totally miss it in another.

[Steve Andrews]

Re: Instructing two way data exchange?

Robin,

As Stan's example illustrates, while the equals sign is often used to assign a value to a variable it is also a Comparison Operator. From the help files under "Comparison Operators" you will find:

Comparison operators compare two expressions which must be of the same type (either character, numeric, or date) and will yield a logical result (i.e., TRUE or FALSE). Any expression involving a comparison operator is called a logical expression.

Steve

[MoGrace]

Re: Instructing two way data exchange?

Robin,

As Stan's example illustrates, while the equals sign is often used to assign a value to a variable it is also a Comparison Operator. From the help files under "Comparison Operators" you will find:


Steve

Thanks for the help file location - I didn't know where to look for it.

[Stan Mathews]

Re: Instructing two way data exchange?

I believe the parentheses are included only for clarity.

Try this as a script.

nlevel = 1

test1 = nLevel = 1
test2 = nLevel = 2

ui_msg_box("Test1",""+test1)
ui_msg_box("Test2",""+test2)

[MoGrace]

Re: Instructing two way data exchange?

I believe the parentheses are included only for clarity.

Try this as a script.

nlevel = 1
 
test1 = nLevel = 1
test2 = nLevel = 2
 
ui_msg_box("Test1",""+test1)
ui_msg_box("Test2",""+test2)

I think what threw me off was seeing this used to pass a value to a table using Xbasic. Which is why I have been poking around here again lately - you guys write much better scripts than I do. You also write much more complicated scripts than I do ;) But I want to learn.

[Stan Mathews]

Re: Instructing two way data exchange?

But I want to learn.

Glad to hear it.

Can you see why this doesn't work (It took me a bit to see it.)?

a_rose = 9
? a_rose = a_rose = a_rose
ERROR: Argument is incorrect data type

Apologies to Gertrude Stein.

[Steve Andrews]

Re: Instructing two way data exchange?

I would assume that it doesn't work because (a) a_rose becomes a numeric type with the first assignment and (b) it is being assigned a logical value in the second line.

[Stan Mathews]

Re: Instructing two way data exchange?

I would assume that it doesn't work because (a) a_rose becomes a numeric type with the first assignment and (b) it is being assigned a logical value in the second line.

Shucks, you may have spoiled it for Robin.

Actually the issue is deeper than is immediately obvious.

a_rose = 9
Dim rslt as l
rslt =  a_rose = a_rose = a_rose
ERROR: Argument is incorrect data type

When a_rose = a_rose = a_rose is being evaluated in whichever direction, one pair (a_rose = a_rose) is evaluated to a logical value and then that logical value is evaluated against the original value (9). I think that evaluation triggers the error.

Probably what you meant.

[andycaps]

Re: Instructing two way data exchange?

Hello Stan,
This post has diversified a bit, isn�t it great?
I have a question for you on the first setbox.zip - I added another product to the products table without a price and added the same product to the vendorprice table and entered in 4 diff prices. I thon open the view: main, clicked to the second record and selected a price. I then checked the product table to see if the price was shown, it does not show! Logically it should, what is wrong with this? Can you try adding a new product to your version and see f you can emulate this you�re side.

In my main application I have about 100 items and although I have manually selected the prices using the check box only the first record in the products file appears to have its cost changed, however - nothing from record 2 onwards?

Also - if I change say record 6's cost the cost in record 1 in the products table changes?

Any ideas
Thanks
Andy

[MoGrace]

Re: Instructing two way data exchange?

Glad to hear it.

Can you see why this doesn't work (It took me a bit to see it.)?

a_rose = 9
? a_rose = a_rose = a_rose
ERROR: Argument is incorrect data type

Apologies to Gertrude Stein.

That's where the parenthesis comes in handy.

You can't change the variable type which is what the first a_rose in the statement is attempting to do.

Now if we can only help Andy... (Sorry for derailing your post :o )

[andycaps]

Re: Instructing two way data exchange?

Hi,
Not complaining i just think it's really great that a simple posting can spark new avenues of thought, and the really good thing is we ALL learn a little bit more every time somebody posts and replies to the content, it's really brilliant...
Thanks
Andy