String Function

String functions:

There are many useful string functions in Visual Basic 6. The string functions are defined in the "Strings" module. Search in the object browser.

The string functions are explained below:

Left:

The Left function extracts characters from the left of the string.

Syntax:

Left(string, n) 

n is the number of characters to be extracted.

Example:

Print Left("Visual", 3)

Output:
Vis

Right:

The Right function extracts characters from the right of the string.

Syntax:
Right(string, n)
String is the character string, n is the number of characters to be extracted.

Example:

Print Right("Visual", 3)
Output:
ual

Mid:

Use the the Mid function to extract characters from the middle of the string.

Syntax:

Mid(string, m, n)

String is the character string, the extracted string will begin at mth character, n is the number of characters to be extracted.

Example:          
Print Mid("Visual", 3, 2)

Output:
su

Len:

The Len function calculates the number of characters in a string.

Example:

Private Sub cmdCount_Click()
Dim str As String
str = "Visual Basic"
Print Len(str)
End Sub

Output:
12

InStr:

The InStr function returns the position of first occurrence of a sub-string contained in a string.

Syntax:

Instr(str1, str2)

Example:

Dim str As String
str = "Visual Basic"
Print InStr(str, "Basic")

Output:

 8

Chr & Asc:

 The Chr function converts an ASCII value to character and Asc function converts the character to ASCII.

 Syntax:

Chr(ASCII value)

Asc(chr)

Example:

Print Chr(65)

Output:
A

Example:
Print Asc("A")

Output:
65

Chr(9) and chr(13) are the Tab and Carriage-return characters respectively.

Example:

Print "Hello" & Chr(9) & "world"

Output:
Hello        world

Print "Hello" & Chr(13) & "world"

Output:

Hello

world

Str:
The Str function returns the string representation of a number.

Syntax:

Str(n)

Example:       

Print str(5) + str(7)

Output: 57

LCase & UCase:

The LCase function converts an upper case string to lower case and the UCase converts a lower case string to upper case.

Example:

Private Sub cmdChangeCase_Click()

Dim s As String

s = "HELLO"

Print LCase(s)

End Sub

Output:

hello

Example:

Dim s As String

s = "hello"

Print UCase(s)

Output:
HELLO

Trim:

The Trim function returns a string without leading and trailing spaces.

Example:

Dim s As String

s = "                      HELLO"

Print Trim(s)

Output:
HELLO

LTrim & RTrim:
The Ltrim function trims leading spaces and the RTrim function trims trailing spaces from a string.

StrReverse:

The StrReverse function reverses a string.

Example:

Print StrReverse("Basic")

Output:
cisaB

Space:
Space function returns a specific number of spaces.

Example:

Print Space(10) + StrReverse("Basic")

Output:

           Basic

10 spaces before Basic

StrConv:
The StrConv function converts the string into a particular case, e.g upper case, lower case and proper case.

Example:
Print StrConv("hello", vbUpperCase)

Output:
 HELLO

Print StrConv("hello", vbProperCase)

Output:
Hello

StrComp:
The StrComp function compares two strings to check whether they match or not. It returns 0, if the two strings match with one another.

str = StrComp("vb", "vb", vbTextCompare) 'Returns 0

str = StrComp("vb", "VB", vbTextCompare) 'Returns 0

str = StrComp("vb", "VB", vbBinaryCompare) 'Returns 1

If the optional argument is vbTextCompare then this is a case insensitive comparison, if vbBinaryCompare then it's a case sensitive comparison.

Tab:

The Tab(n) function lets the string be displayed at nth position.

Example:

Print Tab(20) ; "Language"

Output:

                    Language