num

num* ( expression : string {, separator : string } ) : number
num ( expression : number ) : number
num ( expression : boolean ) : number

Parameter	Type		Description
expression	any	→	Character for which you want to get the code
separator	string	→	Decimal separator
Result	number	←	Numeric form of the expression parameter

Description

The num command returns the numeric form of the string, boolean or numeric expression you pass in expression. The optional separator parameter designates a decimal separator for evaluating string type expressions.

String Expressions

If expression consists only of one or more alphabetic characters, num returns a zero. If expression includes alphabetic and numeric characters, the command ignores the alphabetic characters. Thus, it transforms the string "a1b2c3" into the number 123.

There are three reserved characters that num treats specially: the decimal separator as defined in the system (if the separator parameter is not passed), the hyphen “-”, and “e” or “E”. These characters are interpreted as numeric format characters.

• The decimal separator is interpreted as a decimal place and must appear embedded in a numeric string. By default, the command uses the decimal separator set by the operating system. You can modify this character using the separator parameter (see below).
• The hyphen causes the number or exponent to be negative. The hyphen must appear before any negative numeric characters or after the “e” for an exponent. Except for the “e” character, if a hyphen is embedded in a numeric string, the portion of the string after the hyphen is ignored. For example, num("123-456") returns 123, but num("-9") returns -9.
• The e or E causes any numeric characters to its right to be interpreted as the power of an exponent. The “e” must be embedded in a numeric string. Thus, num("123e–2") returns 1.23. Note that when the string includes more than one "e", conversion might give different results under Mac OS and under Windows.

The separator parameter designates a custom decimal separator for evaluating the expression. When the string to be evaluated is expressed with a decimal separator different from the system operator, the command returns an incorrect result. The separator parameter can be used in this case to obtain a correct evaluation. When this parameter is passed, the command does not take the system decimal separator into account. You can pass one or more characters.

Boolean Expressions

If you pass a boolean expression, num returns 1 if the expression is true; otherwise, it returns 0 (zero).

Numeric Expressions

If you pass a numeric expression in the expression parameter, num returns the value passed in the expression parameter as is. This can be useful more particularly in the case of generic programming.

Undefined Expressions

If expression evaluates to undefined, the command returns 0 (zero). This is useful when you expect the result of an expression (e.g. an object attribute) to be a number, even if it can be undefined.

Example 1

The following example illustrates how num works when passed a string argument.

 var vResult : number
 vResult = num("ABCD") // vResult gets 0
 vResult = num("A1B2C3") // vResult gets 123
 vResult = num("123") // vResult gets 123
 vResult = num("123.4") // vResult gets 123.4
 vResult = num("–123") // vResult gets –123
 vResult = num("–123e2") // vResult gets –12300

Example 2

This example compares the results obtained depending on the separator:

 var thestring : string
 var thenum : number
 thestring = "33 333,33"
 thenum = num(thestring) // 3333333
 thenum = num(thestring,",") // 33333.33

See also

bool
string