module Comparable(T)

Overview

The Comparable mixin is used by classes whose objects may be ordered.

Including types must provide an #<=> method, which compares the receiver against another object, returning:

• a negative number if self is less than the other object
• a positive number if self is greater than the other object
• 0 if self is equal to the other object
• nil if self and the other object are not comparable

Comparable uses #<=> to implement the conventional comparison operators (#<, #<=, #==, #>=, and #>). All of these return false when #<=> returns nil.

Note that returning nil is only useful when defining a partial comparable relationship. One such example is float values: they are generally comparable, except for NaN. If none of the values of a type are comparable between each other, Comparable shouldn't be included.

NOTE When nil is returned from #<=>, Array#sort and related sorting methods will perform slightly slower.

Direct including types

• Array(T)
• BigDecimal
• BigFloat
• BigInt
• BigRational
• Char
• Enum
• Float
• Int
• Number
• Path
• Pointer(T)
• SemanticVersion
• SemanticVersion::Prerelease
• Slice(T)
• String
• Symbol
• Time
• Time::Span
• Tuple(*T)

Defined in:

Instance Method Summary

• #<(other : T)

  Compares this object to other based on the receiver’s #<=> method, returning true if it returns a negative number.

• #<=(other : T)

  Compares this object to other based on the receiver’s #<=> method, returning true if it returns a value equal or less then 0.

• #<=>(other : T)

  The comparison operator.

• #==(other : T)

  Compares this object to other based on the receiver’s #<=> method, returning true if it returns 0.

• #>(other : T)

  Compares this object to other based on the receiver’s #<=> method, returning true if it returns a value greater then 0.

• #>=(other : T)

  Compares this object to other based on the receiver’s #<=> method, returning true if it returns a value equal or greater than 0.

• #clamp(min, max)

  Clamps a value between min and max.

• #clamp(range : Range)

  Clamps a value within range.

Instance Method Detail

# Sort in a descending way:
[3, 1, 2].sort { |x, y| y <=> x } # => [3, 2, 1]

# Sort in an ascending way:
[3, 1, 2].sort { |x, y| x <=> y } # => [1, 2, 3]

5.clamp(10, 100)   # => 10
50.clamp(10, 100)  # => 50
500.clamp(10, 100) # => 100

5.clamp(10, nil)  # => 10
50.clamp(10, nil) # => 50

5.clamp(nil, 10)  # => 5
50.clamp(nil, 10) # => 10

5.clamp(10..100)   # => 10
50.clamp(10..100)  # => 50
500.clamp(10..100) # => 100

5.clamp(10..)  # => 10
50.clamp(10..) # => 50

5.clamp(..10)  # => 5
50.clamp(..10) # => 10