Logic Functions

case

Evaluate one of several statements, depending on a sequence of conditions. Use instead of nested if functions.

case(condition1 : boolean, result1 : any,

     condition2 : boolean, result2 : any,

...  fallback : any) : any

If condition1 is true, this function returns result1; if condition2 is true, this function returns result2; and so on. If none of the conditions are true, this function returns the last argument fallback. The types of all resultant arguments and the fallback argument must be convertible to some common type. The number of arguments must be odd. Also, see the switch function.

For example:

`case(false, "good", true, "ok", "bad")` returns ok

`case(calc("Value") < 1500, "Low", calc("Value") < 1650, "Medium-Low", calc("Value") < 1800, "Medium-High", "High")` when Value is 1550, result is Medium-Low

  add "Age Group" ```case(value("Age") < 1, "Infant",
   value("Age") < 5, "Toddler",
   value("Age") < 13, "Child", 
   value("Age") < 20, "Teen", 
   value("Age") < 30, "Young Adult",
   value("Age") < 65, "Adult",
   "Older Adult")```

adds the Age Group text column to the cBase based on the Age

For an application, see Binning Data in DivePort Administrator Help.

if

Conditionally evaluate another expression.

if(condition : boolean,

   if_true : any,

   if_false : any) : any

If condition is true, then if_true is evaluated, otherwise if_false is evaluated. This function implicitly promotes the types of if_true and if_false to match, meaning the types of if_true and if_false must be convertible to some common type. For example, if one is "fixed100" and the other is "integer", the resulting type is "fixed100".

On the other hand, if if_true is a string and if_false is an integer, a type error results.

For example:

`if(true, 20, 30)` returns 20

`if(false, 50, 100)` returns 100

`if(is_null(value("Last Well Visit Date")), null, date_number(today()) - date_number(value("Last Well Visit Date")))` returns null if the last well visit date is null, otherwise returns the number of days between today and the last well visit date.

TIP: A deeply nested if (that is an if within an if within an if and so on) can be replaced with a switch() expression for a more efficient operation.

match

Return a number indicating which of several values is equal to a target value.

match(target : any, value1 : any, value2 : any,... : any) : integer

If target is equal to value1, this function returns 1; if target is equal to value2, this function returns 2; and so on. If none of the values are matched, this function returns 0.

For example:

`match("alice", "alice", "bob", "charlie")` returns 1

`match("fred", "alice", "bob", "charlie")` returns 0

`match("charlie", "alice", "bob", "charlie")` returns 3

switch

Evaluate one of several statements, depending on the value of an expression. The switch function can be used as shorthand for a chain of if functions.

switch(value : any,

      candidate1 : any, result1 : any,

      candidate2 : any, result2 : any,...

      fallback : any) : any

If value is equal to candidate1, this function returns result1; if value is equal to candidate2, this function returns result2; and so on. If none of the candidates are matched, this function returns the last argument fallback. The types of all resultant arguments and the fallback argument must be convertible to some common type. The number of arguments must be even. See also case.

For example:

`switch(value("thing"), 1, "foo", 2, "bar", 4, "baz", "unknown")`

result is `if(value("thing")=1, "foo", if(value("thing")=2, "bar", if(value("thing")=4, "baz", "unknown")))`.

`switch(4, 1, "foo", 2, "bar", 4, "baz", "unknown")`

result is "baz".

calc "Timeframe_anchor" ```

switch(param("Timeframe"),"7 Days",

offset(calc("the_anchor"),"day",-7),"14 Days",

offset(calc("the_anchor"),"day",-14),"21 Days",

offset(calc("the_anchor"),"day",-21),

offset(calc("the_anchor"),"day",-30))```

sets the Timeframe_anchor using an offset based on the value of the Timeframe parameter.