programming-for-dummies

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Using Operators
Table 5-1
Mathematical Operators
Mathematical Operator Purpose Example
+ Addition 5 + 3.4
- Subtraction 203.9 – 9.12
* Multiplication 39 * 146.7
/ Division 45 / 8.41
% Modula division 35 % 9 = 8
(returns the remainder)
** Exponentiation 2**3 = 8
If you divide two integers with the / operator, the answer will be rounded to
the nearest integer. If you want to return a decimal value, at least one of the
numbers must be written as a decimal value such as 2.0 / 3 or 2 / 3.0. If
you just type 2 / 3, the answer will be 0.
Relational operators compare two values and return a True or a False
value. The seven comparison operators available are shown in Table 5-2.
Table 5-2
Relational Operators
Relational Operator
Purpose
== Equal
=== Identical
!= Not equal
< Less than
Greater than
>= Greater than or equal to
Ruby uses three equal signs (===) to compare to values and determine if they’re
of the same data type. For example, Ruby treats 1.0 and 1 as identical because
both are numbers, but 1.0 and “1.0” wouldn’t be considered equal
because one is a number and the other is a different data type (a string).
Logical operators compare two Boolean values (True or False) and return
a single True or False value, as shown in Table 5-3.