Strings module

The Strings module groups together the runtime's text-processing primitives --- measuring strings, looking inside them, building new ones from old ones, splitting and joining arrays of them, and formatting non-string values as text. Most members come in two callable forms: a $-suffixed form (e.g. Left$) that returns a String, and an unsuffixed form (e.g. Left) that returns a Variant (String) and propagates Null through the call. Several also have a B variant --- AscB, ChrB, InStrB, LeftB, LenB, MidB, RightB --- that operates on byte positions rather than character positions, for use with byte-buffer data held in a String.

Length and character codes

Len returns the number of characters in a string, or --- when given a non-string variable --- the number of bytes the variable occupies. Asc returns the character code of a string's first character; Chr is its inverse, building a single-character string from a code point. The W variants (AscW, ChrW) work in Unicode regardless of the system code page.

Debug.Print Len("Hello")            ' 5
Debug.Print Asc("A")                ' 65
Debug.Print Chr(65)                 ' "A"

Searching and comparing

StrComp compares two strings and returns -1, 0, or 1 to report which is greater (or equal). InStr and InStrRev return the position of one string inside another, scanning forward from a chosen start position or backward from one. All three accept an optional compare argument controlling whether the comparison is case-sensitive (vbBinaryCompare), case-insensitive (vbTextCompare), or governed by the surrounding Option Compare setting (vbUseCompareOption). Note that InStrRev swaps the order of the haystack and needle arguments relative to InStr.

Debug.Print InStr("Hello, world", "o")           ' 5  (first match, forward)
Debug.Print InStrRev("Hello, world", "o")        ' 9  (first match, reverse)
Debug.Print StrComp("ABC", "abc", vbTextCompare) ' 0  (equal under text compare)

Substrings, padding, and trimming

Left, Mid, and Right extract a substring from the start, middle, or end of a string. Mid doubles as an l-value via the Mid = statement, which writes characters back into a string in place. Space returns a run of spaces and String returns a run of any chosen character --- both useful for padding fixed-width output. LTrim, RTrim, and Trim strip leading, trailing, or both kinds of whitespace from a string.

Dim S As String
S = "  Hello, world  "
Debug.Print "[" & Trim(S) & "]"     ' "[Hello, world]"
Debug.Print Left(Trim(S), 5)        ' "Hello"
Debug.Print String(3, "*") & " " & Space(2) & "!"   ' "***   !"

Case folding and other transformations

LCase and UCase fold a string to lowercase or uppercase. StrReverse reverses the character order. StrConv bundles a wider set of conversions --- case folding, proper-casing, narrow/wide and Hiragana/Katakana mapping for DBCS locales, and Unicode-to-ANSI byte-array round-tripping --- selected by an additive flag argument.

Debug.Print UCase("Hello")               ' "HELLO"
Debug.Print StrReverse("Hello")          ' "olleH"
Debug.Print StrConv("hello world", vbProperCase)   ' "Hello World"

Splitting, joining, replacing, filtering

Split breaks a string apart at a delimiter into a zero-based array of substrings; Join reverses the operation, gluing an array back together with a chosen separator between elements. Replace substitutes one substring for another across a string, optionally limited to a fixed number of replacements or starting from a given offset. Filter reduces a string array to only those elements that contain --- or, with include set to False, do not contain --- a chosen substring.

Dim Parts() As String
Parts = Split("red,green,blue", ",")
Debug.Print Join(Parts, " / ")              ' "red / green / blue"
Debug.Print Replace("red,green,blue", ",", "; ")  ' "red; green; blue"

Formatting values as text

Format is the general-purpose formatter: it takes any expression --- number, date, or string --- together with a named or user-defined format string, and returns the rendered text. The four named-formatter functions FormatCurrency, FormatNumber, FormatPercent, and FormatDateTime wrap the most common cases with explicit parameters in place of a format string, so the call site reads as the intent rather than as a recipe. MonthName and WeekdayName return the localised name (or abbreviation) of a month or day of the week, given its numeric index.

Debug.Print Format(1234.5, "#,##0.00")         ' "1,234.50"
Debug.Print FormatCurrency(1234.5)             ' "$1,234.50"   (US locale)
Debug.Print FormatDateTime(Now, vbLongDate)    ' "Saturday, May 9, 2026"
Debug.Print MonthName(1)                       ' "January"

Members

• Asc -- returns the character code of the first character in a string
• Chr -- returns the character associated with a character code
• Filter -- returns a subset of a string array matching (or not matching) a substring
• Format -- formats an expression according to a format expression
• FormatCurrency -- formats an expression as a currency string
• FormatDateTime -- formats an expression as a date/time string
• FormatNumber -- formats an expression as a numeric string
• FormatPercent -- formats an expression as a percent string
• InStr -- returns the position of one string within another
• InStrRev -- returns the position of one string within another, searching from the end
• Join -- concatenates a string array using a given delimiter
• LCase -- returns a string converted to lowercase
• Left -- returns a leftmost substring of a string
• Len -- returns the length of a string, or the storage size of a variable
• LTrim -- removes leading spaces from a string
• Mid -- returns a substring of a string
• MonthName -- returns the name of the specified month
• Replace -- replaces substrings within a string
• Right -- returns a rightmost substring of a string
• RTrim -- removes trailing spaces from a string
• Space -- returns a string of spaces
• Split -- splits a string into a string array on a delimiter
• StrComp -- compares two strings
• StrConv -- converts a string to a specified format
• String -- returns a string of repeating characters
• StrReverse -- reverses the order of characters of a string
• Trim -- removes leading and trailing spaces from a string
• UCase -- returns a string converted to uppercase
• WeekdayName -- returns the name of the specified day of the week