ReDim Statement

Declares or redefines variables or arrays.

Syntax:

ReDim Statement diagram


ReDim [Preserve] variable [(start To end)] [As type-name][, variable2 [(start To end)] [As type-name][,...]]

Optionally, add the Preserve keyword to preserve the contents of the array that is redimensioned. ReDim can only be used in subroutines.

Parameters:

variable: Any variable or array name.

typename: Keyword that declares the data type of a variable.

primitive data types fragment

Byte: Byte variable (0-255)

Boolean: Boolean variable (True, False)

Currency: Currency variable (Currency with 4 Decimal places)

Ngày: biến ngày

Double: Double-precision floating-point variable (1,79769313486232 x 10E308 - 4,94065645841247 x 10E-324)

Số nguyên: biến số nguyên (-32768 - 32767)

Dài: biến số nguyên dài (-2.147.483.648 - 2.147.483.647)

Object: Object variable (Note: this variable can only subsequently be defined with Set!)

Đơn: biến chấm động chính xác đơn (3,402823 × 10E38 - 1,401298 × 10E-45).

Chuỗi: biến chuỗi chứa nhiều nhất 64.000 ASCII ký tự.

Variant: Variant variable type (contains all types, specified by definition). If a type name is not specified, variables are automatically defined as Variant Type, unless a statement from DefBool to DefVar is used.

object: Universal Network object (UNO) object or ClassModule object instance.

char: Special character that declares the data type of a variable.

Type declaration characters fragment

In LibreOffice Basic, you do not need to declare variables explicitly. However, you need to declare arrays before you can use them. You can declare a variable with the Dim statement, using commas (,) to separate multiple declarations. To declare a variable type, enter a type-declaration character following the name or use a corresponding type keyword name.

Declaration character

Variable type name

%

Integer

&

Long

!

Single

#

Double

$

String

@

Currency


array: Array declaration.

array fragment

start, end: Numerical values or constants that define the number of elements (NumberElements=(end-start)+1) and the index range.

start and end can be numerical expressions if ReDim is applied at the procedure level.

LibreOffice Basic hỗ trợ mảng một/nhiều chiều được xác định bởi một kiểu biến đã ghi rõ. Mảng thích hợp nếu chương trình chứa danh sách hay bảng bạn muốn chỉnh sửa. Lợi ích của mảng là có thể đặt địa chỉ của mỗi phần tử riêng tùy theo chỉ số, mà có thể được cấu tạo dạng biểu thức thuộc số hay biến.

Arrays are declared with the Dim statement. There are multiple ways to define the index range:


  Dim text(20) As String ' 21 elements numbered from 0 to 20
  Dim value(5 to 25) As Integer ' 21 values numbered from 5 to 25
  Dim amount(-15 to 5) As Currency ' 21 amounts (including 0), numbered from -15 to 5
  REM Two-dimensional data field
  Dim table$(20,2) ' 63 items; from 0 to 20 level 1, from 0 to 20 level 2 and from 0 to 20 level 3.

You can declare an array types as dynamic if a ReDim statement defines the number of dimensions in the subroutine or the function that contains the array. Generally, you can only define an array dimension once, and you cannot modify it. Within a subroutine, you can declare an array with ReDim. You can only define dimensions with numeric expressions. This ensures that the fields are only as large as necessary.

Thí dụ :


Sub ExampleRedim
    Dim iVar() As Integer, iCount As Byte
    ReDim iVar(5) As Integer
    For iCount = 1 To 5
        iVar(iCount) = iCount
    Next iCount
    ReDim iVar(10) As Integer
    For iCount = 1 To 10
        iVar(iCount) = iCount
    Next iCount
End Sub

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