Ruby | Enumerable one? function

The one?() of enumerable is an inbuilt method in Ruby returns a boolean value true if exactly one of the object in the enumerable satisfies the given condition, else it returns false. If a pattern is given, it returns true if any one object matches with exactly pattern.

Syntax enu.one? { |obj| block } or enu.one?(pattern)

Parameters: The function takes two types of parameters, one is the object and the block, while the other is the pattern.

Return Value: It returns a boolean value.

Example #1:

# Ruby program for one? method in Enumerable 
    
# Initialize an enumerable 
enu1 = [10, 19, 18]    
    
# checks if all numbers are greater  
# than 4 or not  
res1 = enu1.one? { |num| num>4}  
  
# prints the result  
puts res1  
  
  
# checks if all numbers are greater  
# than 4 or not  
res2 = enu1.one? { |num| num>=19}  
  
# prints the result  
puts res2  

Output:

false
true

Example #2:

# Ruby program for one? method in Enumerable 
    
# Initialize an enumerable 
enu1 = [10, 19, 20]    
    
# Checks 
res1 = enu1.one?(Numeric) 
  
# prints the result  
puts res1  
  
# Initialize 
enu2 = [nil, 1] 
  
# Checks  
res2 = enu2.one?  
# prints the result  
puts res2  

Output:

false
true

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