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Stored procedures
Executes a procedure on each element of a source array and returns the results in a WLanguage array.
Example
arrValue is array of int = [1,2,3,4,5]
arrTriple is array of int
 
// Construct an array with the values multiplied by three
arrTriple = Map(arrValue, AValue => AValue * 3)
// arrTriple contains [3, 6, 9, 12, 15]
// -> apply lowercase to all the strings in the array
// (Prefix syntax)
arr1 is array of strings = ["A", "b", "C"]
arr1 = arr1.Map(X => Lower(X))
// arr1 = ["a", "b", "c"]
Syntax
<Result> = Map(<Source array> , <Operation to perform>)
<Result>: WLanguage array
Array that contains the result of the procedure executed for each element of the <Source array>.
<Source array>: WLanguage array
Name of Array variable to use. This array must be a one-dimensional array.
<Operation to perform>: WLanguage procedure
Name of the WLanguage procedure to be executed for each element of the <Source array>. This procedure can be:
  • a global or local procedure,
  • an internal procedure.
It is also possible to directly use a lambda procedure.
Remarks

Operating mode

The <Operation to perform> procedure is called for each element of the source array by passing this element as a parameter.
The results of all calls are stored in the <Result> array.
Remark: You can use the following functions in the same line of code: Filter, Reduce, Apply, Min, Max, Sum, Mean, CheckAnyTrue, CheckAnyFalse, CheckAllTrue, CheckAllFalse.
Related Examples:
Filter / Map / Reduce Unit examples (WINDEV): Filter / Map / Reduce
[ + ] This example shows how to use the Filter / Map / Reduce functions.
The Filter / Map / Reduce concept allows performing operations on sets of data in a remarkably concise way.
Filter is used to filter an array of elements in a customized way (with a callback procedure).
Map is used to transform an array of elements, also with a callback procedure.
Reduce is used to aggregate data in a customized way with a callback procedure.
Here, this example is used to calculate the average age of women among the users displayed in the table below.
Business / UI classification: Neutral code
Component: wd260vm.dll
Minimum version required
  • Version 25
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