How to find a given number is prime or not in ruby?

def check_prime n
    (2..n-1).each do |no|
         return false if n % no == 0
    end
    true
end

How to multiply the array elements in ruby?

a= [1,2,3,4,5,6,7,8]

Scenarios 1:
a.reduce(:*)

Scenarios 2:
b=1

a.each do |e|
  b=b*e
end

Factorial program using ruby

def factorial_no
  yield
end

n=gets.to_i
factorial_no do
  (1..n).reduce(:*)
end

How to Find the sum of total elements in an array using ruby?

a= [1,2,3,4,54,656,76,43,560]

Solution 1:

a.inject(&:+)

output: =>1399

Solution 2:

b = 0
a.each do |e|
  b+=e
end
b

output: =>1399

Find the uniq elements in an array without using ruby default method?

a = [1, 2, 3, 4, 5, 6, 4, 3, 2, 1, 4, 5, 4, 34, 76]

Solution:

b = Hash.new 0

a.each do |k|
  b[k] += 1
end

b.keys

Output:
=> [1, 2, 3, 4, 5, 6, 34, 76]

How to remove the duplicate pair in an array using ruby?

Scenario 1
 
a = ['R1,R2','R3,R4','R5,R6', 'R2,R1', 'R4,R3']

Result:

a.uniq {|x| x.split(",").sort.join(',')}

Output => ["R1,R2", "R3,R4", "R5,R6"]

Scenario 2

a = ['R1,R2','R3,R4','R5,R6', 'R2,R1', 'R4,R3']

Result:  

require 'set'
a.uniq {|x| Set.new(x.split(','))} 

Output => ["R1,R2", "R3,R4", "R5,R6"] 

Display the * values in triangle shape in ruby

for i in 1..10
  for j in 1..i
    print ('*')
  end
  print ("\n")
end

output:
*
**
***
****
*****
******
*******
********
*********
**********