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:

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# 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 

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Output:

false
true

Example #2:

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# 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 

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Output:

false
true


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