======Number======

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 [[PTPScript:Operators:Type Casting|Number typecast operators]]).

For example:

<code ptpscript>
{ 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 }
</code>

<note tip>
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.
</note>

====Converting to Number====

To explicitly convert a value to Number, the [[PTPScript:Operators:Type Casting|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|Boolean]] **''false''** is converted to ''0'', and **''true''** is converted to ''1''
  * [[String|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.
  * [[Array|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.