Visual Basic 6.0 has various string handling functions for different string related operations. These functions can be used to solve different string related problems without using loops. Some of the string related functions are listed below:
| Function | Description | Return Type |
| Len (String) | Returns the Length of the string. | Integer |
| LenB (String) | Returns the number of bytes in a string. | Integer |
| Asc (String) | Returns the ASCII value of the first character in String. | Integer |
| Chr (Integer) | Returns a String with the corresponding ASCII code. | String |
| Left$ (String, x) Left (String, x) | Returns x characters from the start of String. | String |
| Right$ (String,x) Right (String, x) | Returns x characters from the end of String. | String |
| Mid$(String, x, y) Mid (String, x, y) | Returns y characters from String, starting at the x'th character. | String |
| Cstr (x) | Returns the string representation of x (localized). | String |
| Str$ (x) Str (x) | Returns the string representation of x (not localized). | String |
| UCase$ (String) UCase (String) | Coverts String to Upper Case. | String |
| LCase$ (String) LCase (String) | Converts String to Lower Case. | String |
| InStr ([start,] string1, string2 [, compare]) | Returns a Long specifying the position of one string within another. | Long |
| InStrRev(string1, string2[, start, [, compare]]) | Returns a Long specifying the position of one string within another from backward. | Long |
| String$(number,character) | Returns a string containing a repeating character string of the length specified. | String |
StrComp(String1, String2, Attribute) |
Returns 0 if strings are equal, 1 if String1 sorts after String2 and –1 if String1 sorts ahead of String2. | Integer |
| Replace$ (or Replace)(expression, find, replacewith[, start[, count[, compare]]]) | Returns a string in which a specified substring has been replaced with another substring a specified number of times. | String |
| StrReverse$ (string)
StrReverse (string) |
Reverse the String. | String |
| LTrim$ (String)
LTrim (String) |
Removes leading blank spaces from a string. | String |
| RTrim$ (String)
RTrim (String) |
Removes trailing blank spaces from a string. | String |
| Trim$ (String)
Trim (String) |
Removes both leading and trailing blank spaces from a string. | String |
| Split(expression[, delimiter[, count[, compare]]]) | Splits a string into separate elements based on a delimiter (such as a comma or space) and stores the resulting elements in a zero-based array | zero-based, one-dimensional array containing a specified number of substrings. |
| Join (list[, delimiter]) | Joins (Concatenates) elements of an array into an output string. | String |
| Filter(InputStrings, Value[, Include[, Compare]]) | Returns a zero-based array containing subset of a string array based on a specified filter criteria. | String |
The Attribute Field of StrComp Function takes
Binary : Performs a binary comparison, based on a sort order derived from the internal binary representations of the characters.
Text : Performs a text comparison, based on a case-insensitive text sort order determined by your application's current culture information.
Try following piece of Code. This Function will Trim all spaces from the sentence.
1: Function TrimAllSpaces(data As String)
2: Dim str As String
3: Dim length As Integer
4: data = Trim(data)
5: length = Len(data)
6: For i = 1 To length Step 2
7: str = str & Trim(Mid(data, i, 2))
8: Next i
9: lblOutput.Caption = str
10: End Function
The 4th line data = Trim(data) trims all leading and trailing spaces and store the result to data. The 5th line stores the length of the string (data) to variable length. The 7th line str = str & Trim(Mid(data, i, 2)) extracts 2 characters from the ith position of the string, trim leading and trailing spaces and concatenate the result to variable str.
Call function TrimAllSpaces on Click event of Button Trim
1: Private Sub cmdTrim_Click()
2: TrimAllSpaces txtInput.Text
3: End Sub
Run the project , enter a string of your choice and click the "Trim" button.
The screen shot shows a run of the project using the code above.
Using Function UCase, LCase and StrReverse
Function to convert Lower Case to Upper Case
1: Function upperCase(data As String)
2: data = UCase(data)
3: lblOutput.Caption = data
4: End Function
Function to convert Upper Case to Lower Case
1: Function lowerCase(data As String)
2: data = LCase(data)
3: lblOutput.Caption = data
4: End Function
Function to reverse a string
1: Function stringReverse(data As String)
2: data = StrReverse(data)
3: lblOutput.Caption = data
4: End Function
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