Excel - VBA functions references (Conversion functions)

Visual Basic for Applications

Conversion functions

1，Asc：

Returns an Integer representing the character code corresponding to the first letter in a string.

Asc(string)

The required string argument is any valid string expression. If the string contains no characters, a run-time error occurs.

参数是一个字符串，返回第一个字符的ASCII码值。

The range for returns is 0–255 on non-DBCS systems, but -32768–32767 on DBCS systems.

The AscB function is used with byte data contained in a string. Instead of returning the character code for the first character, AscB returns the first byte. The AscW function returns the Unicode character code except on platforms where Unicode is not supported, in which case, the behavior is identical to the Asc function.

The functions Chr(), ChrB(), and ChrW() are the opposite of Asc(), AscB(), and AscW(). The Chr() functions convert an integer to a character string.

Example

Dim MyNumber

MyNumber = Asc("A")    ' Returns 65.

MyNumber = Asc("a")    ' Returns 97.

MyNumber = Asc("Apple")    ' Returns 65.

2，Chr function

Returns a String containing the character associated with the specified character code.

Syntax

Chr(charcode)

ChrB(charcode)

ChrW(charcode)

The ChrB function is used with byte data contained in a String. Instead of returning a character, which may be one or two bytes, ChrB always returns a single byte.

The functions Asc(), AscB(), and AscW() are the opposite of Chr(), ChrB(), and ChrW(). The Asc() functions convert a string to an integer.

Example

Dim MyChar

MyChar = Chr(65)    ' Returns A.

MyChar = Chr(97)    ' Returns a.

MyChar = Chr(62)    ' Returns >.

MyChar = Chr(37)    ' Returns %.

3，CVErr function

Returns a Variant of subtype Error containing an error number specified by the user.

Syntax

CVErr(errornumber)

The required errornumber argument is any valid error number.

Remarks

Use the CVErr function to create user-defined errors in user-created procedures. For example, if you create a function that accepts several arguments and normally returns a string, you can have your function evaluate the input arguments to ensure they are within acceptable range. If they are not, it is likely your function will not return what you expect. In this event, CVErr allows you to return an error number that tells you what action to take.

Note that implicit conversion of an Error is not allowed. For example, you can't directly assign the return value of CVErr to a variable that is not a Variant. However, you can perform an explicit conversion (by using CInt, CDbl, and so on) of the value returned by CVErr and assign that to a variable of the appropriate data type.

Example

This example uses the CVErr function to return a Variant whose VarType is vbError (10). The user-defined function CalculateDouble returns an error if the argument passed to it isn't a number. Use CVErr to return user-defined errors from user-defined procedures or to defer handling of a run-time error. Use the IsError function to test if the value represents an error.

' Call CalculateDouble with an error-producing argument.

Sub Test()

    Debug.Print CalculateDouble("345.45robert")

End Sub

' Define CalculateDouble Function procedure.

Function CalculateDouble(Number)

    If IsNumeric(Number) Then

        CalculateDouble = Number * 2    ' Return result.

    Else

        CalculateDouble = CVErr(2001)    ' Return a user-defined error

    End If    ' number.

End Function

4，Format function

Returns a Variant (String) containing an expression formatted according to instructions contained in a format expression.

Syntax

Format(Expression, [ Format ], [ FirstDayOfWeek ], [ FirstWeekOfYear ])

The Format function syntax has these parts.

Part	Description
Expression	Required. Any valid expression.
Format	Optional. A valid named or user-defined format expression.
FirstDayOfWeek	Optional. A constant that specifies the first day of the week.
FirstWeekOfYear	Optional. A constant that specifies the first week of the year.

Settings

The firstdayofweek argument has these settings.

Constant	Value	Description
vbUseSystem	0	Use NLS API setting.
vbSunday	1	Sunday (default)
vbMonday	2	Monday
vbTuesday	3	Tuesday
vbWednesday	4	Wednesday
vbThursday	5	Thursday
vbFriday	6	Friday
vbSaturday	7	Saturday

The firstweekofyear argument has these settings.

Constant	Value	Description
vbUseSystem	0	Use NLS API setting.
vbFirstJan1	1	Start with week in which January 1 occurs (default).
vbFirstFourDays	2	Start with the first week that has at least four days in the year.
vbFirstFullWeek	3	Start with the first full week of the year.

Remarks

To format	Do this
Numbers	Use predefined named numeric formats or create user-defined numeric formats.
Dates and times	Use predefined named date/time formats or create user-defined date/time formats.
Date and time serial numbers	Use date and time formats or numeric formats.
Strings	Create your own user-defined string formats.

Format truncates format to 257 characters.

If you try to format a number without specifying format, Format provides functionality similar to the Str function, although it is internationally aware. However, positive numbers formatted as strings using Format don't include a leading space reserved for the sign of the value; those converted using Str retain the leading space.

If you are formatting a non-localized numeric string, you should use a user-defined numeric format to ensure that you get the look you want.

If the Calendar property setting is Gregorian and format specifies date formatting, the supplied expression must be Gregorian. If the Visual Basic Calendar property setting is Hijri, the supplied expression must be Hijri.

Hijri日期（伊斯兰教历），公历日期（格里高利历）。

If the calendar is Gregorian, the meaning of format expression symbols is unchanged. If the calendar is Hijri, all date format symbols (for example, dddd, mmmm, yyyy ) have the same meaning but apply to the Hijri calendar. Format symbols remain in English; symbols that result in text display (for example, AM and PM) display the string (English or Arabic) associated with that symbol. The range of certain symbols changes when the calendar is Hijri.

Date symbols

Symbol	Range
d	1-31 (Day of month, with no leading zero)
dd	01-31 (Day of month, with a leading zero)
w	1-7 (Day of week, starting with Sunday = 1)
ww	1-53 (Week of year, with no leading zero; Week 1 starts on Jan 1)
m	1-12 (Month of year, with no leading zero, starting with January = 1)
mm	01-12 (Month of year, with a leading zero, starting with January = 01)
mmm	Displays abbreviated month names (Hijri month names have no abbreviations)
mmmm	Displays full month names
y	1-366 (Day of year)
yy	00-99 (Last two digits of year)
yyyy	100-9999 (Three- or Four-digit year)

Time symbols

Symbol	Range
h	0-23 (1-12 with "AM" or "PM" appended) (Hour of day, with no leading zero)
hh	00-23 (01-12 with "AM" or "PM" appended) (Hour of day, with a leading zero)
n	0-59 (Minute of hour, with no leading zero)
nn	00-59 (Minute of hour, with a leading zero)
m	0-59 (Minute of hour, with no leading zero). Only if preceded by h or hh
mm	00-59 (Minute of hour, with a leading zero). Only if preceded by h or hh
s	0-59 (Second of minute, with no leading zero)
ss	00-59 (Second of minute, with a leading zero)

Example

This example shows various uses of the Format function to format values using both named formats and user-defined formats. For the date separator (/), time separator (:), and AM/ PM literal, the actual formatted output displayed by your system depends on the locale settings on which the code is running. When times and dates are displayed in the development environment, the short time format and short date format of the code locale are used. When displayed by running code, the short time format and short date format of the system locale are used, which may differ from the code locale. For this example, English/U.S. is assumed. MyTime and MyDate are displayed in the development environment using current system short time setting and short date setting.

Dim MyTime, MyDate, MyStr

MyTime = #17:04:23#

MyDate = #January 27, 1993#

' Returns current system time in the system-defined long time format.

MyStr = Format(Time, "Long Time")

' Returns current system date in the system-defined long date format.

MyStr = Format(Date, "Long Date")

MyStr = Format(MyTime, "h:m:s")    ' Returns "17:4:23".

MyStr = Format(MyTime, "hh:mm:ss am/pm")    ' Returns "05:04:23 pm".

MyStr = Format(MyTime, "hh:mm:ss AM/PM")    ' Returns "05:04:23 PM".

MyStr = Format(MyDate, "dddd, mmm d yyyy")    ' Returns "Wednesday, Jan 27 1993".

' If format is not supplied, a string is returned.

MyStr = Format(23)    ' Returns "23".

' User-defined formats.

MyStr = Format(5459.4, "##,##0.00")    ' Returns "5,459.40".

MyStr = Format(334.9, "###0.00")    ' Returns "334.90".

MyStr = Format(5, "0.00%")    ' Returns "500.00%".

MyStr = Format("HELLO", "<")    ' Returns "hello".

MyStr = Format("This is it", ">")    ' Returns "THIS IS IT".

Different formats for different numeric values

A user-defined format expression for numbers can have from one to four sections separated by semicolons. If the format argument contains one of the named numeric formats, only one section is allowed.

If you use	The result is
One section only	The format expression applies to all values.
Two sections	The first section applies to positive values and zeros, the second to negative values.
Three sections	The first section applies to positive values, the second to negative values, and the third to zeros.
Four sections	The first section applies to positive values, the second to negative values, the third to zeros, and the fourth to Null values.

"$#,##0;($#,##0)"

If you include semicolons with nothing between them, the missing section is printed using the format of the positive value. For example, the following format displays positive and negative values using the format in the first section and displays "Zero" if the value is zero.

"$#,##0;;\Z\e\r\o"

Different formats for different string values

A format expression for strings can have one section or two sections separated by a semicolon (;).

If you use	The result is
One section only	The format applies to all string data.
Two sections	The first section applies to string data, the second to Null values and zero-length strings ("").

Named date/time formats

The following table identifies the predefined date and time format names.

Format name	Description
General Date	Display a date and/or time, for example, 4/3/93 05:34 PM. If there is no fractional part, display only a date, for example, 4/3/93. If there is no integer part, display time only, for example, 05:34 PM. Date display is determined by your system settings.
Long Date	Display a date according to your system's long date format.
Medium Date	Display a date using the medium date format appropriate for the language version of the host application.
Short Date	Display a date using your system's short date format.
Long Time	Display a time using your system's long time format; includes hours, minutes, seconds.
Medium Time	Display time in 12-hour format using hours and minutes and the AM/PM designator.
Short Time	Display a time using the 24-hour format, for example, 17:45.

Named numeric formats

The following table identifies the predefined numeric format names.

Format name	Description
General Number	Display number with no thousand separator.
Currency	Display number with thousand separator, if appropriate; display two digits to the right of the decimal separator. Output is based on system locale settings.
Fixed	Display at least one digit to the left and two digits to the right of the decimal separator.
Standard	Display number with thousand separator, at least one digit to the left and two digits to the right of the decimal separator.
Percent	Display number multiplied by 100 with a percent sign (%) appended to the right; always display two digits to the right of the decimal separator.
Scientific	Use standard scientific notation.
Yes/No	Display No if number is 0; otherwise, display Yes.
True/False	Display False if number is 0; otherwise, display True.
On/Off	Display Off if number is 0; otherwise, display On.

User-defined string formats

Use any of the following characters to create a format expression for strings.

Character	Description
@	Character placeholder. Display a character or a space. If the string has a character in the position where the at symbol (@) appears in the format string, display it; otherwise, display a space in that position. Placeholders are filled from right to left unless there is an exclamation point character (!) in the format string.
&	Character placeholder. Display a character or nothing. If the string has a character in the position where the ampersand (&) appears, display it; otherwise, display nothing. Placeholders are filled from right to left unless there is an exclamation point character (!) in the format string.
<	Force lowercase. Display all characters in lowercase format.
>	Force uppercase. Display all characters in uppercase format.
!	Force left to right fill of placeholders. The default is to fill placeholders from right to left.

User-defined date/time formats

The following table identifies characters you can use to create user-defined date/time formats.

Character	Description
(:)	Time separator. In some locales, other characters may be used to represent the time separator. The time separator separates hours, minutes, and seconds when time values are formatted. The actual character used as the time separator in formatted output is determined by your system settings.
(/)	Date separator. In some locales, other characters may be used to represent the date separator. The date separator separates the day, month, and year when date values are formatted. The actual character used as the date separator in formatted output is determined by your system settings.
c	Display the date as ddddd and display the time as ttttt, in that order. Display only date information if there is no fractional part to the date serial number; display only time information if there is no integer portion.
d	Display the day as a number without a leading zero (1–31).
dd	Display the day as a number with a leading zero (01–31).
ddd	Display the day as an abbreviation (Sun–Sat). Localized.
dddd	Display the day as a full name (Sunday–Saturday). Localized.
ddddd	Display the date as a complete date (including day, month, and year), formatted according to your system's short date format setting. The default short date format is m/d/yy.
dddddd	Display a date serial number as a complete date (including day, month, and year) formatted according to the long date setting recognized by your system. The default long date format is mmmm dd, yyyy.
w	Display the day of the week as a number (1 for Sunday through 7 for Saturday).
ww	Display the week of the year as a number (1–54).
m	Display the month as a number without a leading zero (1–12). If m immediately follows h or hh, the minute rather than the month is displayed.
mm	Display the month as a number with a leading zero (01–12). If m immediately follows h or hh, the minute rather than the month is displayed.
mmm	Display the month as an abbreviation (Jan–Dec). Localized.
mmmm	Display the month as a full month name (January–December). Localized.
q	Display the quarter of the year as a number (1–4).
y	Display the day of the year as a number (1–366).
yy	Display the year as a 2-digit number (00–99).
yyyy	Display the year as a 4-digit number (100–9999).
h	Display the hour as a number without a leading zero (0–23).
hh	Display the hour as a number with a leading zero (00–23).
n	Display the minute as a number without a leading zero (0–59).
nn	Display the minute as a number with a leading zero (00–59).
s	Display the second as a number without a leading zero (0–59).
ss	Display the second as a number with a leading zero (00–59).
ttttt	Display a time as a complete time (including hour, minute, and second), formatted using the time separator defined by the time format recognized by your system. A leading zero is displayed if the leading zero option is selected and the time is before 10:00 A.M. or P.M. The default time format is h:mm:ss.
AM/PM	Use the 12-hour clock and display an uppercase AM with any hour before noon; display an uppercase PM with any hour between noon and 11:59 P.M.
am/pm	Use the 12-hour clock and display a lowercase AM with any hour before noon; display a lowercase PM with any hour between noon and 11:59 P.M.
A/P	Use the 12-hour clock and display an uppercase A with any hour before noon; display an uppercase P with any hour between noon and 11:59 P.M.
a/p	Use the 12-hour clock and display a lowercase A with any hour before noon; display a lowercase P with any hour between noon and 11:59 P.M.
AMPM	Use the 12-hour clock and display the AM string literal as defined by your system with any hour before noon; display the PM string literal as defined by your system with any hour between noon and 11:59 P.M. AMPM can be either uppercase or lowercase, but the case of the string displayed matches the string as defined by your system settings. The default format is AM/PM. If your system is set to 24-hour clock, the string is typical set to a zero-length string.

User-defined numeric formats

The following table identifies characters you can use to create user-defined number formats.

Character	Description
None	Display the number with no formatting.
(0)	Digit placeholder. Display a digit or a zero. If the expression has a digit in the position where the 0 appears in the format string, display it; otherwise, display a zero in that position.If the number has fewer digits than there are zeros (on either side of the decimal) in the format expression, display leading or trailing zeros. If the number has more digits to the right of the decimal separator than there are zeros to the right of the decimal separator in the format expression, round the number to as many decimal places as there are zeros. If the number has more digits to the left of the decimal separator than there are zeros to the left of the decimal separator in the format expression, display the extra digits without modification.
(#)	Digit placeholder. Display a digit or nothing. If the expression has a digit in the position where the # appears in the format string, display it; otherwise, display nothing in that position. This symbol works like the 0 digit placeholder, except that leading and trailing zeros aren't displayed if the number has the same or fewer digits than there are # characters on either side of the decimal separator in the format expression.
(.)	Decimal placeholder. In some locales, a comma is used as the decimal separator. The decimal placeholder determines how many digits are displayed to the left and right of the decimal separator. If the format expression contains only number signs to the left of this symbol, numbers smaller than 1 begin with a decimal separator. To display a leading zero displayed with fractional numbers, use 0 as the first digit placeholder to the left of the decimal separator. The actual character used as a decimal placeholder in the formatted output depends on the Number Format recognized by your system.
(%)	Percentage placeholder. The expression is multiplied by 100. The percent character (%) is inserted in the position where it appears in the format string.
(,)	Thousand separator. In some locales, a period is used as a thousand separator. The thousand separator separates thousands from hundreds within a number that has four or more places to the left of the decimal separator. Standard use of the thousand separator is specified if the format contains a thousand separator surrounded by digit placeholders (0 or #). Two adjacent thousand separators or a thousand separator immediately to the left of the decimal separator (whether or not a decimal is specified) means "scale the number by dividing it by 1000, rounding as needed." For example, you can use the format string "##0,," to represent 100 million as 100. Numbers smaller than 1 million are displayed as 0. Two adjacent thousand separators in any position other than immediately to the left of the decimal separator are treated simply as specifying the use of a thousand separator. The actual character used as the thousand separator in the formatted output depends on the Number Format recognized by your system.
(:)	Time separator. In some locales, other characters may be used to represent the time separator. The time separator separates hours, minutes, and seconds when time values are formatted. The actual character used as the time separator in formatted output is determined by your system settings.
(/)	Date separator. In some locales, other characters may be used to represent the date separator. The date separator separates the day, month, and year when date values are formatted. The actual character used as the date separator in formatted output is determined by your system settings.
(E- E+ e- e+)	Scientific format. If the format expression contains at least one digit placeholder (0 or #) to the right of E-, E+, e-, or e+, the number is displayed in scientific format and E or e is inserted between the number and its exponent. The number of digit placeholders to the right determines the number of digits in the exponent. Use E- or e- to place a minus sign next to negative exponents. Use E+ or e+ to place a minus sign next to negative exponents and a plus sign next to positive exponents.
- + $ ( )	Display a literal character. To display a character other than one of those listed, precede it with a backslash (\) or enclose it in double quotation marks (" ").
(\)	Display the next character in the format string. To display a character that has special meaning as a literal character, precede it with a backslash (\). The backslash itself isn't displayed. Using a backslash is the same as enclosing the next character in double quotation marks. To display a backslash, use two backslashes (\\). Examples of characters that can't be displayed as literal characters are the date-formatting and time-formatting characters (a, c, d, h, m, n, p, q, s, t, w, y, /, and :), the numeric-formatting characters (#, 0, %, E, e, comma, and period), and the string-formatting characters (@, &, <, >, and !).
("ABC")	Display the string inside the double quotation marks (" "). To include a string in format from within code, you must use Chr(34) to enclose the text (34 is the character code for a quotation mark (")).

5，Hex function

Returns a String representing the hexadecimal value of a number.

Syntax

Hex(number)

The required number argument is any valid numeric expression or string expression.

If number is	Hex returns
-2,147,483,648 to 2,147,483,647	Up to eight hexadecimal characters
Null	Null
Empty	Zero (0)

Remarks

If number is not a whole number, it is rounded to the nearest whole number before being evaluated.

For the opposite of Hex, precede a hexadecimal value with &H. For example, Hex(255) returns the string FF and &HFF returns the number 255.

Example

This example uses the Hex function to return the hexadecimal value of a number.

This example uses the Hex function to return the hexadecimal value of a number.

Dim MyHex

MyHex = Hex(5)    ' Returns 5.

MyHex = Hex(10)    ' Returns A.

MyHex = Hex(459)    ' Returns 1CB.

6, Oct function

Returns a Variant (String) representing the octal value of a number.

Syntax

Oct(number)

The required number argument is any valid numeric expression or string expression.

Remarks

If number is not already a whole number, it is rounded to the nearest whole number before being evaluated.

If number is	Oct returns
Null	Null
Empty	Zero (0)
Any other number	Up to 11 octal characters

You can represent octal numbers directly by preceding numbers in the proper range with &O. For example, &O10 is the octal notation for decimal 8.

Example

This example uses the Oct function to return the octal value of a number.

Dim MyOct

MyOct = Oct(4)     ' Returns 4.

MyOct = Oct(8)    ' Returns 10.

MyOct = Oct(459)    ' Returns 713.

7，Str function

Returns a Variant (String) representation of a number.

Syntax

Str(number)

The required number argument is a Long containing any valid numeric expression.

Remarks

When numbers are converted to strings, a leading space is always reserved for the sign of number. If number is positive, the returned string contains a leading space and the plus sign is implied.

Use the Format function to convert numeric values that you want formatted as dates, times, or currency or in other user-defined formats. Unlike Str, the Format function doesn't include a leading space for the sign of number.

Example

This example uses the Str function to return a string representation of a number. When a number is converted to a string, a leading space is always reserved for its sign.

Dim MyString

MyString = Str(459)    ' Returns " 459".

MyString = Str(-459.65)    ' Returns "-459.65".

MyString = Str(459.001)    ' Returns " 459.001".

8，Val function

Returns the numbers contained in a string as a numeric value of appropriate type.

Syntax

Val(string)

The required string argument is any valid string expression.

Remarks

The Val function stops reading the string at the first character that it can't recognize as part of a number. Symbols and characters that are often considered parts of numeric values, such as dollar signs and commas, are not recognized.

However, the function recognizes the radix prefixes &O (for octal) and &H (for hexadecimal). Blanks, tabs, and linefeed characters are stripped from the argument.

The following returns the value 1615198:

Val("    1615 198th Street N.E.")

In the following code, Val returns the decimal value -1 for the hexadecimal value shown:

Val("&HFFFF")

Example

This example uses the Val function to return the numbers contained in a string.

Dim MyValue

MyValue = Val("2457")    ' Returns 2457.

MyValue = Val(" 2 45 7")    ' Returns 2457.

MyValue = Val("24 and 57")    ' Returns 24.

参考：

Functions (Visual Basic for Applications) | Microsoft Learn