Ruby | Range Class Methods (original) (raw)

Last Updated : 22 Aug, 2022

Ruby provides a Range class. Ruby ranges depict a set of values with a beginning and an end. Values of a range can be numbers, characters, strings or objects. It is constructed using start_point..end_point, start_point…endpoint literals, or with ::new. It provides the flexibility to the code and reduce the size of code. You can also create a range by using Range.new. A range which contains ..(two dots) means running from the starting value to the end value inclusively and if a range contains ...(three dots) means it exclude the end value.
Example:

(1..6).to_a # Output= [1, 2, 3, 4, 5, 6] (1...6).to_a # Output= [1, 2, 3, 4, 5]

Note: In Ruby, Ranges can be created using the objects, as long as the objects can be compared using their <=> operator. To return the next object in sequence, it provides the support to the succ method.

Class Method

new : This method is used to create a range from given start and end value. In this method, if the third parameter is false or excluded, the range includes end-object. Otherwise, it will omit.

Range.new(start, end, exclusive=false)

Example:

Ruby `

Ruby program to illustrate

new Method

a = 12 b = 15

Output will be 12..15

Range.new(a, b, false)

Output:

12..15

Instance Methods

== : This method return true if obj whose starting, ending and value of third parameter is same as rng. Otherwise, it will return false. The return type of this method is boolean.

rng==obj-->true or false

Example: Ruby `

Ruby program to illustrate

the use of == method

Using Range.new class method

a = Range.new(2, 5, false) b = Range.new(2, 5, false)

Using == instance method

a == b

Output:

true

=== : In this method if rng omits its end, then return rng.start <= value < rng.end and if rng is inclusive, then it return rng.start <= value<= rng.end. Conveniently, === is the comparison operator and case statements uses this.

rng===value --> true or false

Example: Ruby `

Ruby program to illustrate the use

of === method by case statement

taking case statement

case 25.67

when 1...55 then puts "Lower" when 55...85 then puts "Medium" when 85...100 then puts "Upper" end

Output:

Lower

begin : This method return first object of rng.

rng.begin --> obj

Example: Ruby `

Ruby program to illustrate

the use of begin method

Creating range using the new method

b = Range.new(3, 9, false)

using begin instance method

b.begin

Output:

each : This method is used to iterate over elements of rng, by passing each in turn to the block.

rng.each{|j| block} --> rng

Example: Ruby `

Ruby program to illustrate

the use of each method

using each method

(40..45).each do |i| print i, '....' end

Output:

40....41....42....43....44....45....

end : This method returns the end object of rng.

rng.end --> obj

Example: Ruby `

Ruby program to illustrate

the use of end method

using end method

a = Range.new(3, 9, false) a.end

Output:

eql? : This method check if obj and rng are equal in terms of start, end and exclusive flag. If obj contains the same value of start, end and exclusive flag as rng then it returns true, otherwise it returns false.

rng.eql?(obj) --> true or false

Example: Ruby `

Ruby program to illustrate

the use of eql? method

Constructing ranges

a = Range.new(2, 5, false) b = Range.new(2, 5, false)

using eql? method

a.eql?(b)

Output:

true

exclude_end? : This method return true if the end of the rng is omitted, otherwise return false.

rng.exclude_end? --> true or false

Example: Ruby `

Ruby program to illustrate the

use of exclude_end? method

constructing range

a = Range.new(3, 9, false)

using exclude_end? method

a.exclude_end?

Output:

false

first : This method return starting object of rng.

rng.first --> obj

Example: Ruby `

Ruby program to illustrate

the use of first method

constructing range

a = Range.new(3, 9, false)

using the first method

a.first

Output:

last : This method return the last object of rng.

rng.last --> obj

Example: Ruby `

Ruby program to illustrate

the use of last method

constructing range

a = Range.new(3, 9, false)

using last method

a.last

Output:

member? : This method check if the given value is the member of rng. If the given value is the member of rng then it return true, otherwise return false.

rng.member?(value) --> true or false

Example: Ruby `

Ruby program to illustrate

the use of member? method

taking a range

a = 1..10

using member? method

a.member?(5)

Output:

true

include? : This method returns true if obj is an element of rng, false otherwise.

rng.include?(value) --> true or false

Example: Ruby `

Ruby program to illustrate

the use of include? method

using include? method

("A".."G").include?("Z")

Output:

false

step : This method iterates over rng, by passing each nth object to the block. If the range have numbers, addition to one generate successive elements. Otherwise step invokes succ method to iterate range elements.

rng.step(n=1){|obj|block} --> rng

Reference: https://ruby-doc.org/core-1.9.3/Range.html