Explain the concept of scope in Ruby

The range is everywhere: January to December, 0 to 9, 50 to 67 lines, and so on. Ruby supports scopes and allows us to use scopes in multiple ways:

As sequence range

As condition range

As interval range

As a sequence range:

First, and perhaps the most natural use of scope is to express sequences. A sequence has a starting point, an end point, and continuous values in the sequence to produce.

Ruby creates operators in the range `` .. '' and `` ... '' to use these sequences. The two-point form creates an inclusive range, while the three-point form creates a range excluding the specified high value.

(1..5) # ==> 1, 2, 3, 4, 5

(1 ... 5) # ==> 1, 2, 3, 4

('a' .. 'd') # ==> 'a', 'b', 'c', 'd'

The sequence 1..100 as a Range object contains references to two Fixnum objects. If necessary, you can use a to_a method for a series of lists. Try the following example:

#! / usr / bin / ruby

$, = "," # Array value separator

range1 = (1..10) .to_a

range2 = ('bar' .. 'bat'). to_a

puts "# {range1}"

puts "# {range2}"

This will produce the following results:

1, 2, 3, 4, 5, 6, 7, 8, 9, 10

bar, bas, bat

Scope implementation methods that iterate between them and test their content in various ways:

#! / usr / bin / ruby

# Assume a range

digits = 0..9

puts digits.include? (5)

ret = digits.min

puts "Min value is # {ret}"

ret = digits.max

puts "Max value is # {ret}"

ret = digits.reject {| i | i <5}

puts "Rejected values are # {ret}"

digits.each do | digit |

puts "In Loop # {digit}"

end

This will produce the following results:

true

Min value is 0

Max value is 9

Rejected values are 5, 6, 7, 8, 9

In Loop 0

In Loop 1

In Loop 2

In Loop 3

In Loop 4

In Loop 5

In Loop 6

In Loop 7

In Loop 8

In Loop 9

Range as condition:

Ranges can also be used as conditional expressions. For example, the following code snippet prints a set of lines from standard input, with the first line in each group containing the last line of words beginning and ending:

while gets

print if /start/../end/

end

Scopes can use case statements:

#! / usr / bin / ruby

score = 70

result = case score

when 0..40: "Fail"

when 41..60: "Pass"

when 61..70: "Pass with Merit"

when 71..100: "Pass with Distinction"

else "Invalid Score"

end

puts result

This will produce the following results:

Pass with Merit

Interval range:

The last all-around range to use is for interval testing: if any value falls within the interval's time interval, this is an equal operation using ===.

#! / usr / bin / ruby

if ((1..10) === 5)

puts "5 lies in (1..10)"

end

if (('a' .. 'j') === 'c')

puts "c lies in ('a' .. 'j')"

end

if (('a' .. 'j') === 'z')

puts "z lies in ('a' .. 'j')"

end

This will produce the following results:

5 lies in (1..10)

c lies in ('a' .. 'j')