Ruby Monstas

Ranges

Ranges

Ruby allows us to build ranges and then loop through their items.

Building a range

Ranges normally have a start and an end.

Example: from e to q

Range.new("e", "q")
# or
("e".."q")

Methods on Ranges

There are multiple useful methods on ranges:

  • .begin
  • .end
  • .count
  • .cover?(value)
  • .to_a
  • .each

For a full list of methods visit the official Ruby Documentation.

Methods on Ranges: Examples

(Try these in IRB)

(23..42).begin          # => 23
("f".."t").end          # => "t"
(20..30).count          # => 11
("B".."S").cover?("J")  # => true
("abc".."abe").to_a     # => ["abc", "abd", "abe"]

.each

Using the method .each we can iterate through the items

morning_hours = (8..12)

morning_hours.each do |item|
  puts "#{item} is a morning hour"
end

Result

8 is a morning hour
9 is a morning hour
10 is a morning hour
11 is a morning hour
12 is a morning hour

Exclude the last

If we want to exclude the last item within the range, we can do so by using three dots:

("x"..."z").to_a # => ["x", "y"]

Additional Resources

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

What questions do you have?