Numeric.even? / odd? / zero? / between? / clamp
These are predicate methods available on integers and numeric values. They simplify conditional expressions for checking even/odd, zero, sign, and range.
Syntax
# Returns true if the integer is even. integer.even? # Returns true if the integer is odd. integer.odd? # Returns true if the value is zero. number.zero? # Returns true if the value is positive. number.positive? # Returns true if the value is negative. number.negative? # Returns true if the value is between min and max (inclusive). number.between?(min, max) # Clamps the value to the range min..max. number.clamp(min, max) # Returns the infinity state of a Float. float.infinite? # Returns true if the Float is NaN (Not a Number). float.nan?
Method List
| Method | Description |
|---|---|
| even? | Returns true if the integer is even, false if odd. Available on integers only. |
| odd? | Returns true if the integer is odd, false if even. Available on integers only. |
| zero? | Returns true if the value is zero. Works for both integers and floats. |
| positive? | Returns true if the value is positive (zero is not included). |
| negative? | Returns true if the value is negative (zero is not included). |
| between?(min, max) | Returns true if the value is greater than or equal to min and less than or equal to max. |
| clamp(min, max) | Returns the value clamped to the range min..max. If out of range, returns the nearest boundary value. |
| infinite? | Returns 1 for positive infinity, -1 for negative infinity, or nil otherwise. Float only. |
| nan? | Returns true if the value is NaN (Not a Number). Float only. |
Sample Code
# even? / odd?
puts 4.even? # true
puts 7.odd? # true
puts 0.even? # true (0 is even)
# zero? / positive? / negative?
puts 0.zero? # true
puts (-5).negative? # true
puts 3.positive? # true
# between?: Check if a value is within a range.
puts 5.between?(1, 10) # true
puts 15.between?(1, 10) # false
# clamp: Restrict a value to a range.
puts 5.clamp(1, 10) # 5 (already within range)
puts 0.clamp(1, 10) # 1 (clamped to minimum)
puts 15.clamp(1, 10) # 10 (clamped to maximum)
# Practical example: Managing player HP (clamped to 0..100).
hp = 120
hp = hp.clamp(0, 100)
puts "HP: #{hp}" # HP: 100
# infinite? / nan?: Float-specific state checks.
puts (1.0 / 0).infinite? # 1 (positive infinity)
puts (-1.0 / 0).infinite? # -1 (negative infinity)
puts (0.0 / 0).nan? # true (NaN)
Notes
By Ruby convention, methods that return a boolean value end with ?. Using these methods makes conditional expressions read almost like natural English (e.g., if n.even?).
clamp is especially useful whenever you need to keep a value within a specific range — such as adjusting slider UI values or managing game status values. Since Ruby 2.7, you can also pass a Range object as the argument (e.g., n.clamp(1..10)).
even? and odd? are only available on integers (Integer). Calling them on a float raises a NoMethodError. If the type is uncertain, convert the value first using Integer(n) or similar.
For iterating over integers, see number.times / upto / downto. For rounding and absolute value, see number.abs / round / ceil / floor.
If you find any errors or copyright issues, please contact us.
シェアする