Picking up where we left off in part 1, today we’re going to take a look at examples 2 through 6 in the Virtual List Charts demo file (the demo has been updated since part 1, so I recommend downloading a fresh copy).
We covered example 1 and most of the general concepts last time, so today we’re mainly going to touch on specific points of interest, but to briefly recap… Continue reading “FM 13: Virtual List Charts, part 2”
Grizzled FileMaker veterans are fond of saying things like, “You ought to know at least three different ways to accomplish any given task.” With that in mind, I hereby submit a third method for calculating the last day of a given month.
Let ( [
theDate = Get ( CurrentDate ) ;
monthNum = Month ( theDate ) ;
yearNum = Year ( theDate ) ;
febLastDay = 28 +
Case (
Mod ( yearNum ; 400 ) = 0 ; 1 ;
Mod ( yearNum ; 100 ) = 0 ; 0 ;
Mod ( yearNum ; 4 ) = 0 ; 1 ;
0
) ;
dayNum = Choose ( monthNum ; "" ; 31 ; febLastDay ; 31 ;
30 ; 31 ; 30 ; 31 ; 31 ; 30 ; 31 ; 30 ; 31
)
] ;
Date ( monthNum ; dayNum ; yearNum )
) // end let
If you read yesterday’s post, you may have noted a resemblance between this calculation and its predecessor, at least as far as the “Let” portion goes. The main difference is the addition of a dayNum variable populated via the Choose() function.
In case you’re not comfortable with Choose(), its format is
Choose (
test ; result if test = 0 { ; result if test = 1 ; result if test = 2... }
)
…where “test” is any non-negative whole number, and the results in braces are optional. At first this function may seem confusing but it turns out to be a very compact replacement for the Case() function, under a strictly defined set of circumstances.
Say, for example, in a table called “test”, you have a field called “score”, which can contain any integer between 0 and 9, and you want convert that value to its corresponding name (“zero,” “one,” “two”, etc.). You could certainly accomplish this with Case() and the statement might look like this:
Case (
test::score = 0 ; "zero" ;
test::score = 1 ; "one" ;
test::score = 2 ; "two" ;
test::score = 3 ; "three" ;
test::score = 4 ; "four" ;
test::score = 5 ; "five" ;
test::score = 6 ; "six" ;
test::score = 7 ; "seven" ;
test::score = 8 ; "eight" ;
test::score = 9 ; "nine"
)
The exact same result can be obtained far more economically thus:
Choose ( test::score ;
"zero" ; "one" ; "two" ; "three" ; "four" ;
"five" ; "six" ; "seven" ; "eight" ; "nine"
)
Essentially, Choose uses test::score as a pointer to the correct “result”, via what’s known as a zero-based index, so a test::score value of 0 corresponds to the first result, a test::score of 1 corresponds to the second result, etc.
In the case of our Last Day of the Month problem, there is no month number of 0, only 1 through 12, so our first result is "" to accommodate the non-existent zero result.
