API reference · Arrays

Exchange

Swap two Variant values in the caller through ByRef arguments.

FunctionArrays→VariantSource L48

Signature#

Function Exchange(ByRef val_a, ByRef val_b) As Variant

Parameters#

Parameter	VBA type	Default	Description
`val_a`	`Variant`ByRef	Required	First value. The parameter has no explicit As clause, so its type is Variant. It is replaced with the original val_b.
`val_b`	`Variant`ByRef	Required	Second Variant value, replaced with the original val_a. Pass writable variables of compatible type.

Returns#

Variant containing Empty. This function never assigns a value to its function name; the useful result is the change to both ByRef arguments.

Example#

SEE THE TRANSFORMATIONSwap the two variables

Before

BeforeValues / state

No array dimensions

Item	Value
debit	125.5
credit	80

After

AfterValues / state

No array dimensions

Item	Value
debit	80
credit	125.5

The variables change in place. The function itself returns Empty.

Shaded headers are array indices, not data. Quoted cells are text. Values shown are derived from the source, not an Excel execution.

Sub ExampleExchange()
    Dim a As New Arrays
    Dim debit As Variant, credit As Variant
    Dim ignored As Variant

    debit = 125.5
    credit = 80
    ignored = a.Exchange(debit, credit)
    Debug.Print debit, credit   ' Expected: 80, 125.5
    Debug.Print IsEmpty(ignored) ' Expected: True
End Sub

Behavior and edge cases#

This is the public Arrays function that deliberately changes its input arguments. Most other functions accept vArr ByVal and return an output array.
The implementation uses ordinary Variant assignment through a temporary variable. It performs no array-shape or type validation.
Although declared as a Function, it has no meaningful return value. Assign the return to an ignored Variant or invoke it with Call.
For objects requiring Set, this routine is not an object-reference swap. Arrays and other non-scalar values follow VBA assignment behavior.

Performance#

Three value assignments. For scalar values, time and auxiliary storage are O(1). Copying array-valued Variants can require work and storage proportional to their contents.

View implementation

Function Exchange(ByRef val_a, ByRef val_b) As Variant
    'Swaps two values passed by reference

    Dim vTemp       As Variant
    Dim temp        As Variant

    temp = val_b
    val_b = val_a
    val_a = temp
End Function