如果使用begin..end或begin...end，這會建立Range實例，代表指定的範圍，begin..end表示包括end，begin...end表示不包括end。例如：
>> 1..5
=> 1..5
>> (1..5).class
=> Range
>> (1..5).each { |i| puts i}
1
2
3
4
5
=> 1..5
>> (1...5).each { |i| puts i }
1
2
3
4
=> 1...5
>>
=> 1..5
>> (1..5).class
=> Range
>> (1..5).each { |i| puts i}
1
2
3
4
5
=> 1..5
>> (1...5).each { |i| puts i }
1
2
3
4
=> 1...5
>>
可以使用begin方法得知範圍起點，使用end方法得知範圍指定終點，使用exclude_end?得知範圍是否排除終點。例如：
>> r = 1..5
=> 1..5
>> r.begin
=> 1
>> r.end
=> 5
>> r.exclude_end?
=> false
>> r = 1...5
=> 1...5
>> r.begin
=> 1
>> r.end
=> 5
>> r.exclude_end?
=> true
>>
=> 1..5
>> r.begin
=> 1
>> r.end
=> 5
>> r.exclude_end?
=> false
>> r = 1...5
=> 1...5
>> r.begin
=> 1
>> r.end
=> 5
>> r.exclude_end?
=> true
>>
範圍不僅可以是整數，也可以是字元或浮點數，只不過浮點數的範圍無法進行迭代。例如：
>> ("a".."g").each { |c| puts c }
a
b
c
d
e
f
g
=> "a".."g"
>> (1.0..3.0).each { |c| puts c }
TypeError: can't iterate from Float
from (irb):79:in `each'
from (irb):79
from C:/Winware/Ruby192/bin/irb:12:in `<main>'
>>
a
b
c
d
e
f
g
=> "a".."g"
>> (1.0..3.0).each { |c| puts c }
TypeError: can't iterate from Float
from (irb):79:in `each'
from (irb):79
from C:/Winware/Ruby192/bin/irb:12:in `<main>'
>>
可以使用include?方法得知範圍物件是否包括某個整數、浮點數或字元。例如：
>> (1.0..3.0).cover? 2.1
=> true
>> (1..10).include? 3
=> true
>> (1..10).include? 0
=> false
>> (1.0..3.0).include? 2.1
=> true
>> (1.0..3.0).include? 3.1
=> false
>> ("a".."g").include? "e"
=> true
>> ("a".."g").include? "x"
=> false
>>
=> true
>> (1..10).include? 3
=> true
>> (1..10).include? 0
=> false
>> (1.0..3.0).include? 2.1
=> true
>> (1.0..3.0).include? 3.1
=> false
>> ("a".."g").include? "e"
=> true
>> ("a".."g").include? "x"
=> false
>>
也可以使用cover?測試物件是否在指定的begin與end之間。例如：
>> (1..10).cover? 3
=> true
>> (1.0..10.0).cover? 3.0
=> true
>> ("a".."m").cover? "x"
=> false
>> ("a".."m").cover? "d"
=> true
>> ("a".."m").cover? "abcd"
=> true
>> ("a".."m").cover? "xyz"
=> false
>>
=> true
>> (1.0..10.0).cover? 3.0
=> true
>> ("a".."m").cover? "x"
=> false
>> ("a".."m").cover? "d"
=> true
>> ("a".."m").cover? "abcd"
=> true
>> ("a".."m").cover? "xyz"
=> false
>>
注意，在(begin..end).cover? var時，為測試是否var>=begin且var<=end（如果是begin...end，則是var<end），所以("a".."m").cover? "abcd"時，是測試"abcd">="a"且"abcd"<="m"。
在介紹字串型態、陣列型態 時，談到[n..m]與[n...m]的索引方式，事實上，[]中的n..m與n...m建立了Range實例。例如：
>> r = 2..5
=> 2..5
>> [1, 2, 3, 4, 5, 6, 7][r]
=> [3, 4, 5, 6]
>> "This is a test"[r]
=> "is i"
>>
=> 2..5
>> [1, 2, 3, 4, 5, 6, 7][r]
=> [3, 4, 5, 6]
>> "This is a test"[r]
=> "is i"
>>
建立Range時，end可以小於begin，不過無法迭代：
>> r = 3..-1
=> 3..-1
>> r.each { |i| puts i }
=> 3..-1
>> r.include? 2
=> false
>> r.cover? 2
=> false
>>
=> 3..-1
>> r.each { |i| puts i }
=> 3..-1
>> r.include? 2
=> false
>> r.cover? 2
=> false
>>
建立Range時，end小於begin，通常為應用於字串與陣列的特例。例如：
>> r = 3..-1
=> 3..-1
>> [1, 2, 3, 4, 5, 6, 7][r]
=> [4, 5, 6, 7]
>> "This is a test"[r]
=> "s is a test"
>>
=> 3..-1
>> [1, 2, 3, 4, 5, 6, 7][r]
=> [4, 5, 6, 7]
>> "This is a test"[r]
=> "s is a test"
>>
可以使用to_a將範圍轉為陣列，不過浮點數範圍不適用，範圍的end小於begin時，會得到空陣列。例如：
>> (1..10).to_a
=> [1, 2, 3, 4, 5, 6, 7, 8, 9, 10]
>> ("a".."c").to_a
=> ["a", "b", "c"]
>> (1.0..3.0).to_a
TypeError: can't iterate from Float
from (irb):14:in `each'
from (irb):14:in `to_a'
from (irb):14
from C:/Winware/Ruby192/bin/irb:12:in `<main>'
>> (10..9).to_a
=> []
>>
=> [1, 2, 3, 4, 5, 6, 7, 8, 9, 10]
>> ("a".."c").to_a
=> ["a", "b", "c"]
>> (1.0..3.0).to_a
TypeError: can't iterate from Float
from (irb):14:in `each'
from (irb):14:in `to_a'
from (irb):14
from C:/Winware/Ruby192/bin/irb:12:in `<main>'
>> (10..9).to_a
=> []
>>