A Number is any whole or decimal, positive or negative number. It is further categorised into Integers ("whole" numbers), and Floats (a floating-point, or real, number). Numbers can only be specified in base-10 (decimal). They can be preceded by a sign symbol (+ or -) to set the sign of the number (note that the sign symbols are also the Number typecast operators).

For example:

{ a = 123 // An integer }
{ a =   0 // An integer }
{ a =  -4 // An integer }
{ b = 1.45 // A float }
{ b = 0.0  // A float }
{ b = -9.6 // A float }

Numbers in standard form, such as -5.4e7 and 4E-11 can be used by converting them from strings, for instance +"4E-11". See Converting to Number below.

Converting to Number

To explicitly convert a value to Number, the Number typecast operator - + - should be used (+ converts as-is, whereas - converts to Number and also reverses the sign). Some operators, such as the numerical multiplication operator - * - also explictly convert a value to Number.

When converting to Number:

  • Boolean false is converted to 0, and true is converted to 1
  • Strings will be converted to Floats if the string contains a number in standard form, or a number with a decimal point in it. In all cases, the first part of the string is used for the conversion, which stops when non-numerical data is found.
  • Arrays are currently converted to the numerical equivalent of their Boolean value. In the future this may well change to give the number of items in the Array.
ptpscript/types/number.txt · Last modified: 2007/01/24 10:15
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