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


Download sample program: String Analyzer

    Replace

    The Replace function finds a sub-string in a string and replaces the sub-string with another.

    Example:

    newvalue = Replace("months", "s", "1") 'Returns month1