Birthday??

[forskare]

I searched the board for and tried a couple of expressions on calculating a person's age. When pressing Evaluate, the correct age is shown. However, when clicking OK, a message appears stating "the equation must return a character string".

What gives?

Thanks, kenn

[Tom Cone Jr]

RE: Birthday??

Ken,

Sounds like a field type mismatch. Changing your script to convert the age to a character string will probably solve it for you.

Check out the Str() function.

-- tom

[David Mason]

RE: Birthday??

Ken,

What is the equation? I have used my own expression for years and have shared it to other users in the past.

Dave

[forskare]

RE: Birthday??

Hi David,

(date()-birthday)/365.25

I'll also check out Tom's suggestion. Birthday is a date field.

Thanks,
Ken

[forskare]

RE: Birthday??

This is supposed to convert to a character string, is it not?

function Age as N(Birthday as D)
' type your code here

Age = year(date())-year(birthday)
if val(right(cdate(birthday),4)) > val(right(cdate(date()),4))
age = age - 1
end if

end function

Thanks,

kenn

[whanigsberg]

RE: Birthday??

Ken,

The function returns a number:

function Age as N[umeric](Birthday as D)

If you are inserting the output of this function into a character field the expression would be

str(age(birthday))

which returns a character string.

Bill

[martinwcole]

RE: Birthday??

'dr. wayne's script
function Age as N(BirthDate as D)
dim today as d
dim yr as n
today=date()
if birthdate today then
age=0 'error trap
exit function
end if
yr=year(birthdate)

yr=year(today)-year(birthdate) - 1
if month(today)>month(birthdate) then
yr=yr+1
elseif month(today)=month(birthdate)then
if day(today)>=day(birthdate) then
yr=yr+1
end if
end if
age=yr
end function

[forskare]

RE: Birthday??

Hi Bill,

I've set the field's structure to Character and defined the field as a calculated field in the field rules and used this script.

STR(AGE(BIRTHDAY))

function Age as C(Birthday as D)
' type your code here

'str(age(birthday))
Age = year(date())-year(birthday)
if val(right(cdate(birthday),4)) > val(right(cdate(date()),4))
age = age - 1
end if

end function

The ages show up when evaluated but on the form it reads: 0.

Rechecked the field's structure; yup it's still a character. I've changed the structure to numeric, still the same. I've changed the function from C to N to Z (no not z, gotta have some humor)

I realize there's a mismatch somewhere, but where?

Now this is getting to the principal of the thing!!

kenn

[Stan Mathews]

RE: Birthday??

You changed the field to character and the function now returns a character.

The principle of the thing is that Alpha doesn't know how to evaluate

STR(AGE(BIRTHDAY))

because STR() is not defined for a character value, which is what AGE(BIRTHDAY) returns.

Imagine STR("A").

[forskare]

RE: Birthday??

Stan, et al,

Sorry I'm so thick headed for something that should be so easy.

AGE(BIRTHDAY) returns 0. when used with:

function Age as N(Birthday as D)

After switching it to:

function Age as C(Birthday as D), the Age(Birthday)function returns 14.000000, 12.000000, etc. when evaluated.
However, when clicking OK, then I get the message, The equation must return a character string. **which is what AGE(BIRTHDAY) returns.**

FWIW, the age field in the table is a Character field set to calculated with the script placed in the expression box.

I'll take this up tomorrow, hopefully with a clearer mind.

kenn

[Tom Cone Jr]

RE: Birthday??

Ken,

the first line in a User Defined Function establishes the 'type' that Alpha Five will use in returning the result of the function.

Early in this thread you were using:

function Age as N(Birthday as D)


This means that Alpha Five is expecting to return the result of the function as a 'N'umeric type. If your function returns a numeric type, and you want to put it in a char field then you have to convert the numeric AFTER the function, but before the assignment to the char field. It's up to the programmer to assure that the script INSIDE the function always results in a numeric result.


Later on in this thread, you started using:

function Age as C(Birthday as D)

This means that Alpha Five is expecting the result to be returned as a 'C'haracter type. So no conversion would be necessary AFTER the function runs. However, it's up to you to make certain that the script INSIDE the function always results in an answer that is of char type. If the script inside the function winds up with a numeric, the fact that your first line specified a char type will not automatically convert it for you. You would have to do the conversion INSIDE the function in this case.

-- tom

[forskare]

RE: Birthday??

I Tom,

Thank you for taking the time for a detailed explanation. I have understood what you said. However, it isn't working like it should. The field structure is Character and I set it to calculated in the field rules with the expression
Str(Age(Birthday)). It results in "0." (minus the ")no matter which record is showing. That's what was frustrating, I knew I was doing it right and when it didn't work, I tried various combinations.

I did a database compact but not all tables will compact including the one I'm using. Therefore, I believe it's corrupted. So, I'll build new tables.

At last, success!! I created a calculated field from the dragdrop list and it works just fine using the above expression.

Thanks again for your support and patience.

kenn