Instrução MID

Artigo
08/08/2011

Replaces a specified number of characters in a String variable with characters from another string.

Mid( _
   ByRef Target As String, _
   ByVal Start As Integer, _
   Optional ByVal Length As Integer _
) = StringExpression

Parts

Target
Required. Name of the String variable to modify.
Start
Required. Integerexpressão. Posição de caractere Target onde a substituição de texto começa. Startusa a um-, com base de índice.
Length
Optional. Integerexpressão. Number of characters to replace. If omitted, all of String is used.
StringExpression
Required. Stringexpressão substitui parte de Target.

Exceções

Exception type	Error number	Condition
ArgumentException	5	Start<= 0 or Length < 0.

See the "Error number" column if you are upgrading Visual Basic 6.0 applications that use unstructured error handling. (Você pode comparar o número do erro contra a Number propriedade.) However, when possible, you should consider replacing such error control with Visão Geral sobre a Manipulação Estruturada de Exceções para o Visual Basic.

Comentários

The number of characters replaced is always less than or equal to the number of characters in Target.

Visual Basic has a Mid function and a Mid statement. These elements both operate on a specified number of characters in a string, but the Mid function returns the characters while the Mid statement replaces the characters. For more information, see Mid.

Observação
The MidB statement of earlier versions of Visual Basic replaces a substring in bytes, rather than characters. It is used primarily for converting strings in double-byte character set (DBCS) applications. All Visual Basic strings are in Unicode, and MidB is no longer supported.

Exemplo

This example uses the Mid statement to replace a specified number of characters in a string variable with characters from another string.

Dim TestString As String
' Initializes string.
TestString = "The dog jumps"
' Returns "The fox jumps".
Mid(TestString, 5, 3) = "fox"
' Returns "The cow jumps".
Mid(TestString, 5) = "cow"
' Returns "The cow jumpe".
Mid(TestString, 5) = "cow jumped over"
' Returns "The duc jumpe".
Mid(TestString, 5, 3) = "duck"