Name
Mid, MidB Functions
Syntax
Mid(string
,start
[,length
])
string
Use: Required
Data Type: String
The expression from which to return a substring.
start
Use: Required
Data Type: Long
The starting position of the substring.
length
Use: Optional
Data Type: Long
The length of the substring.
Return Value
A String.
Description
Returns a substring of a specified length from within a given string.
Rules at a Glance
If
string
contains aNull
, Mid returnsNull
.If
start
is more than the length ofstring
, a zero-length string is returned.If
start
is less than zero, error 5, “Invalid procedure call or argument,” is generated.If
length
is omitted or is greater than the length ofstring
, all characters fromstart
to the end ofstring
are returned.The MidB version of the Mid function is used with byte data held within a string. When using MidB, both
start
andlength
refer to numbers of bytes as opposed to numbers of characters.
Example
The following example is a function that parses a string passed to it as a parameter and writes each word to a dynamic array. Note the use of the InStr function to determine the position of a space, which in this case is the character that can terminate a word:
Public Function ParseString(strString) Dim arr( ) Dim intStart, intEnd, intStrLen, intCtr intCtr = 0 intStart = 1 intStrLen = Len(strString) Redim Preserve arr(10) Do While intStart > 0 intEnd = InStr(intStart, strString, " ") - 1 If intEnd <= 0 Then intEnd = intStrLen If intCtr > UBound(arr) Then Redim Preserve arr(UBound(arr)+10) ...
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