Automatic conversion to a number

Describes the automatic conversion of numbers in OPL functions.

When a function or a method which expects a number as one of its arguments is passed a nonnumeric value, it tries to convert this value to a number using the following rules:

  • A string is parsed as a number literal. If the string does not represent a valid number literal, the conversion yields NaN.

  • The Boolean true yields the number 1.

  • The Boolean false yields the number 0.

  • The null value yields the number 0.

  • A date yields the corresponding number of milliseconds since 00:00:00 UTC, January 1, 1970.

For example, if the Math.sqrt function is passed a string, this string is converted to the number it represents: 


Math.sqrt("25") 5

Similarly, operators which take numeric operands attempt to convert any nonnumeric operands to a number: 


"3" * "4"  12

For operators that can take both strings (concatenation) and numbers (addition), such as +, the conversion to a string takes precedence over the conversion to a number (See Automatic conversion to a string.). In other words, if at least one of the operands is a string, the other operand is converted to a string; if none of the operands is a string, the operands are both converted to numbers. For example: 


"3" + true  "3true"  
3 + true  4

For comparison operators, such as == and >=, the conversion to a number takes precedence over the conversion to a string. In other words, if at least one of the operands is a number, the other operand is converted to a number. If both operands are strings, the comparison is made on strings. For example: 


"10" > "2"  false  
"10" > 2  true