Find in array

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4D v16.3

Find in array


Find in array ( array ; value {; start} ) -> Function result

Parameter	Type	Description
array	Array	Array to search
value	Expression	Value of same type to search in the array
start	Longint	Element at which to start searching
Function result	Longint	Number of the first element in array that matches value

Description

The Find in array command returns the number of the first element in array that matches value.

Find in array can be used with Text, String, Numeric, Date, Pointer, and Boolean arrays. The array and value parameters must be of the same type.

value must match exactly the element to find (the same rules as for the equality operator are applied, see Comparison Operators). If no match is found, Find in array returns –1.

If start is specified, the command starts searching at the element number specified by start. If start is not specified, the command starts searching at element 1.

Example 1

The following project method deletes all empty elements from the string or text array whose pointer is passed as parameter:

  ` CLEAN UP ARRAY project method

  ` CLEAN UP ARRAY ( Pointer )

  ` CLEAN UP ARRAY ( -> Text or String array )

 

 C_POINTER($1)

 Repeat

    $vlElem:=Find in array($1->;"")

    If($vlElem>0)

       DELETE FROM ARRAY($1->;$vlElem)

    End if

 Until($vlElem<0)

After this project method is implemented in a database, you can write:

 ARRAY TEXT(atSomeValues;...)

  ` ...

  ` Do plenty of things with the array

  ` ...

  ` Eliminate empty string elements

 CLEAN UP ARRAY(->atSomeValues)

Example 2

The following project method selects the first element of an array whose pointer is passed as the first parameter that matches the value of the variable or field whose pointer is passed as parameter:

  ` SELECT ELEMENT project method

  ` SELECT ELEMENT ( Pointer ; Pointer)

  ` SELECT ELEMENT ( -> Text or String array ; -> Text or String variable or field )

 

 $1->:=Find in array($1->;$2->)

 If($1->=-1)

    $1->:=0 ` If no element was found, set the array to no selected element

 End if

After this project method is implemented in a database, you can write:

  ` asGender pop-up menu object method

 Case of

    :(Form event=On Load)

       SELECT ELEMENT(->asGender;->[People]Gender)

 

 End case

Note: This example uses the selected element of the array. Keep in mind that the selected element is not meaningful if the array contains more than 32,767 elements (see Arrays and Form Objects). In this case, you need to use a longint variable to store the result of Find in array.