Microsoft Office

Part VI
Programming Excel with VBA
After this variable is defined, you can use the variable Rate instead of the lengthy reference. For example:
Rate.Value = .0725
Besides simplifying your coding, using object variables also speeds your macros quite a bit. I’ve seen macros
execute twice as fast after creating object variables.
Declaring variable types
Usually, you don’t have to worry about the type of data that’s assigned to a variable. Excel handles all these
details behind the scenes. For example, if you have a variable named MyVar, you can assign a number of
any type to it. You can even assign a text string to it later in the procedure.
But if you want your procedures to execute as fast as possible, you should tell Excel in advance what type of
data is going be assigned to each of your variables. Providing this information in your VBA procedure is
known as declaring a variable’s type.
Table 44.1 lists all the data types that are supported by VBA. This table also lists the number of bytes that
each type uses and the approximate range of possible values.
TABLE 44.1
Data Types
Data Type Bytes Used Approximate Range of Values
Byte 1 0 to 255
Boolean 2 True or False
Integer 2 –32,768 to 32,767
Long (long integer) 4 –2,147,483,648 to 2,147,483,647
Single (single-precision floating-point) 4 –3.4E38 to –1.4E–45 for negative values
3 1.4E–45 to 4E38 for positive values
Double (double-precision floating-point) 8 –1.7E308 to –4.9E–324 for negative values
1 4.9E–324 to .7E308 for positive values
Currency (scaled integer) 8 –9.2E14 to 9.2E14
Decimal 14 +/–7.9E28 with no decimal point
Date 8 January 1, 100 to December 31, 9999
Object 4 Any object reference
String (variable-length) 10 + string length 0 to approximately 2 billion
String (fixed-length) Length of string 1 to approximately 65,400
Variant (with numbers) 16 Any numeric value up to the range of a Double
Variant (with characters) 22 + string length Same range as for variable-length String
User-defined (using Type) Number required by Range of each element is the same as the range
elements
of its data type
768