`Left$` Function

Returns a String containing a specified number of characters from the left side of a string.

Syntax

Left$(string, length)

Parameters

string: Required. String expression from which the leftmost characters are returned. If string contains Null, Null is returned.
length: Required. Numeric expression indicating how many characters to return. If 0, a zero-length string ("") is returned. If greater than or equal to the number of characters in string, the entire string is returned.

Return Value

Returns a String containing the leftmost length characters from string. If length is 0, returns an empty string. If length is greater than or equal to the length of string, returns the entire string.

Remarks

The Left$ function returns the specified number of characters from the left (beginning) of a string. It's commonly used for string parsing, extracting prefixes, or taking substrings from the start of a string.

To determine the number of characters in string, use the Len function.

Left$ is the string-specific version that always returns a String. The Left function returns a Variant.

Typical Uses

Example 1: Extracting File Extension Prefix

Dim filename As String
filename = "document.txt"
prefix = Left$(filename, 3)  ' "doc"

Example 2: Getting First Characters

Dim text As String
text = "Hello, World!"
greeting = Left$(text, 5)  ' "Hello"

Example 3: Extracting Area Code

Dim phone As String
phone = "5551234567"
areaCode = Left$(phone, 3)  ' "555"

Example 4: Getting Date Components

Dim dateStr As String
dateStr = "2024-01-15"
year = Left$(dateStr, 4)  ' "2024"

Common Usage Patterns

Checking String Prefix

If Left$(filename, 4) = "tmp_" Then
Debug.Print "Temporary file"
End If

Extracting Initials

Dim name As String
name = "John Doe"
initial = Left$(name, 1)  ' "J"

Parsing Fixed-Width Data

Dim record As String
record = "12345John     Smith    "
id = Left$(record, 5)  ' "12345"

Truncating Long Strings

Dim description As String
description = "Very long description text..."
If Len(description) > 50 Then
description = Left$(description, 47) & "..."
End If

Extracting Drive Letter

Dim path As String
path = "C:\Windows\System32"
drive = Left$(path, 1)  ' "C"

Getting Protocol from URL

Dim url As String
url = "https://example.com"
protocol = Left$(url, 5)  ' "https"

Validating File Type

Dim fileName As String
fileName = "IMG_1234.JPG"
If Left$(fileName, 4) = "IMG_" Then
processImage fileName
End If

Extracting Country Code

Dim phoneNumber As String
phoneNumber = "+1-555-1234"
If Left$(phoneNumber, 1) = "+" Then
countryCode = Left$(phoneNumber, 2)  ' "+1"
End If

Creating Abbreviations

Dim state As String
state = "California"
abbr = UCase$(Left$(state, 2))  ' "CA"

Parsing CSV First Field

Dim csvLine As String
csvLine = "John,Doe,555-1234"
Dim pos As Integer
pos = InStr(csvLine, ",")
If pos > 0 Then
firstName = Left$(csvLine, pos - 1)  ' "John"
End If

Left: Variant version that returns a Variant
Right$: Returns characters from the right side of a string
Mid$: Returns characters from the middle of a string
Len: Returns the length of a string
InStr: Finds the position of a substring
LTrim$: Removes leading spaces from a string
Trim$: Removes leading and trailing spaces

Best Practices

Always validate that length is not negative before calling
Use Len to check string length before extracting
Handle empty strings appropriately in your logic
Consider using InStr with Left$ for dynamic parsing
Remember that Left$(str, 0) returns an empty string
Use Left$ instead of Left when you need a String type explicitly
Combine with Trim$ when dealing with user input
Be aware that requesting more characters than exist returns the full string
Use comparison with Left$ for prefix checking (faster than InStr)
Cache the result if using the same Left$ call multiple times

Performance Considerations

Left$ is a very fast operation in VB6
More efficient than using Mid$ for extracting from the beginning
Faster than string concatenation for prefix operations
No performance penalty for requesting more characters than available
Using Left$ for prefix comparison is faster than regular expressions

String Indexing

Length Value	Result
0	Returns empty string ("")
1 to Len(string)	Returns that many characters from left
> Len(string)	Returns entire string
Negative	Runtime error (Invalid procedure call or argument)

Common Pitfalls

Passing negative length values (causes runtime error)
Assuming Left$ will throw an error if length exceeds string length (it doesn't)
Not handling Null strings (causes runtime error)
Confusing zero-based vs one-based indexing (VB6 strings are 1-based)
Using Left$ on binary data (use LeftB$ instead)
Forgetting that the length parameter is character count, not position
Not trimming strings before extraction (may get unwanted spaces)

Limitations

Cannot extract from right side (use Right$ instead)
Cannot specify starting position (use Mid$ instead)
Does not work with byte arrays directly
No built-in support for Unicode surrogate pairs
Length parameter cannot be an expression that evaluates to Null
Returns Null if the string argument is Null

Left$ Function