Instrucción For… Next

Repeats the statements between the For...Next block a specified number of times.

Sintaxis:

For counter=start To end [Step step]
    bloque de instrucciones
    [Exit For]
    bloque de instrucciones
Next [counter]

  For Each item In list
      bloque de instrucciones
  [Exit For]
      bloque de instrucciones
  Next [item]

Variables:

counter: Loop counter initially assigned the value to the right of the equal sign (start). Only numeric variables are valid. The loop counter increases or decreases according to the variable step until end is passed.

start: Numeric variable that defines the initial value at the beginning of the loop.

end: Numeric variable that defines the final value at the end of the loop.

step: Sets the value by which to increase or decrease the loop counter. If step is not specified, the loop counter is incremented by 1. In this case, end must be greater than start. If you want to decrease counter, end must be less than start, and step must be assigned a negative value.

El bucle For...Next repite todas las instrucciones del bucle tantas veces como especifiquen los parámetros.

As the counter variable is decreased, LibreOffice Basic checks if the end value has been reached. As soon as the counter passes the end value, the loop automatically terminates.

Se pueden anidar instrucciones For...Next. Si no se especifica ninguna variable después de la instrucción Next, Next hace referencia automáticamente a la instrucción For más reciente.

Si se especifica un incremento 0, las instrucciones entre For y Next se repiten indefinidamente.

When counting down the counter variable, LibreOffice Basic checks for overflow or underflow. The loop ends when counter exceeds end (positive Step value) or is less than end (negative Step value).

La instrucción Exit For se utiliza para salir del bucle incondicionalmente. Esta instrucción debe estar incluida dentro del bucle For...Next. Use la instrucción If...Then para comprobar la condición de salida de la forma siguiente:

  For...
      bloque de instrucciones
      If condition = True Then Exit For
      bloque de instrucciones
  Next

In nested For...Next loops, if you exit a loop unconditionally with Exit For, only one loop is exited.

Ejemplos

The following example uses two nested loops to sort a string array with 10 elements ( sEntry() ), that is filled with various contents:

Sub ExampleSort
Dim sEntry(9) As String
Dim iCount As Integer, iCount2 As Integer
Dim sTemp As String
    sEntry = Array("Jerry","Patty","Kurt","Thomas","Michael",_
                 "David","Cathy","Susie","Edward","Christine")
    For iCount = 0 To 9
        For iCount2 = iCount + 1 To 9
            If sEntry(iCount) > sEntry(iCount2) Then
                sTemp = sEntry(iCount)
                sEntry(iCount) = sEntry(iCount2)
                sEntry(iCount2) = sTemp
            End If
        Next iCount2
    Next iCount
    For iCount = 0 To 9
        Print sEntry(iCount)
    Next iCount
End Sub

This explores the content of an array to display each item it contains.

  Sub list_iteration
      cutlery = Array("fork", "knife", "spoon")
      For Each item in cutlery
          Print item
      Next ' item
  End Sub