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Stored procedures
Returns an array containing the elements of a source array for which a procedure returns True.
Versions 27 and later
Java This function is now available for Java applications.
Android This function is now available for Android applications.
Android Widget This function is now available in Android widget mode.
New in version 27
Java This function is now available for Java applications.
Android This function is now available for Android applications.
Android Widget This function is now available in Android widget mode.
Java This function is now available for Java applications.
Android This function is now available for Android applications.
Android Widget This function is now available in Android widget mode.
Example
// Retrieve an array with all the customers
arrCustomer is array of Customer
 
// Construct the array of customers a with negative account balance
arrCustomerNegativeBalance is array of Customer
arrCustomerNegativeBalance = Filter(arrCustomer, ACustomer => ACustomer.Balance<0)
// -> keep even numbers of an array
// (prefix syntax)
arr2 is array of int = [1, 2, 3, 4]
arr2 = arr2.Filter( X => IsEven(X))
// arr2 = [2, 4]
Syntax
<Result> = Filter(<Source array> , <Condition to check>)
<Result>: WLanguage array
Array that contains the elements of the <Source array> for which the <Condition to check> returns True.
<Source array>: WLanguage array
Name of the Array variable to use. This array must be a one-dimensional array.
<Condition to check>: WLanguage procedure
Name of the WLanguage procedure to be executed for each element of the <Source array>. This procedure must return True or False.
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 <Condition to check> procedure is called for each element of the array by passing this element as a parameter.
If the procedure returns True, the element from the source array is stored in the <Result> array.
Remark: You can use the following functions in the same line of code: Map, 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: wd270vm.dll
Minimum version required
  • Version 25
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