In this HackerRank Ruby Enumerable: 'any', 'all', 'none', and 'find' reduce problem solution Ruby offers various enumerables on collections that check for validity of the objects within it.

Consider the following example:

> arr = [1, 2, 3, 4, 5, 6]

=> [1, 2, 3, 4, 5, 6]

> h = {"a" => 1, "b" => 2, "c" => 3}

=> {"a" => 1, "b" => 2, "c" => 3}

The any? method returns true if the block ever returns a value other than false or nil for any element passed to it:

> arr.any? {|a| a % 2 == 0} # checks if any number in the array is even

=> True

> h.any? {|key, value| value.is_a? String} # checks if any value of the Hash object is of the type String

=> False

The all? method returns true if the block never returns false or nil for any element passed to it:

> arr.all? {|a| a.is_a? Integer} # checks if all elements of the array are of the type Integer

=> True

> h.all? {|key, value| key.is_a? String} # checks if all keys of the Hash object are of the type String

=> True

The none? method returns true if the block never returns true for any element passed to it:

> arr.none? {|a| a.nil?} # Checks if none of the elements in the array are of nil type

=> True

> h.none? {|key, value| value < 3} # checks if all values of the Hash object are less than 3

=> False

The find method returns the first element for which block is not false:

> arr.find {|a| a > 5} # returns the first element greater than 5 and `nil` if none satisfies the condition

=> 6

> h.find {|key, value| key == "b"} # returns an Array of the first match [key, value] that satisfies the condition and nil otherwise

=> ["b", 2]

Task

complete the functions declared in your editor below.

HackerRank Ruby Enumerable: 'any', 'all', 'none', and 'find' reduce problem solution


Problem solution.

def func_any(hash)
    # Check and return if any key object within the hash is of the type Integer
    hash.keys.any?{|k| k.is_a?(Integer)}
end

def func_all(hash)
    # Check and return if all the values within the hash are Integers and are < 10
    hash.all?{|k, v| (v.is_a?(Integer) && v < 10)}
end

def func_none(hash)
    # Check and return if none of the values within the hash are nil
    hash.values.none?(&:nil?)
end

def func_find(hash)
    # Check and return the first object that satisfies the property
    # [key, value] pair where the key is an Integer and the value is < 20 
    # or [key, value] pair where the key is a String and the value is a String starting 
    # with the character `a`
    hash.detect{|k, v| ([k, v].all?{|val| val.is_a?(Integer)} && v < 20) || ([k, v].all?{|val| val.is_a?(String)} && v.start_with?('a'))}
end


Second solution.

def func_any(hash)
    # Check and return if any key object within the hash is of the type Integer
    hash.any? {|key, value| key.is_a? Integer}
end

def func_all(hash)
    # Check and return if all the values within the hash are Integers and are < 10
    hash.all? {|key, value| value < 10}
end

def func_none(hash)
    # Check and return if none of the values within the hash are nil
    hash.none? {|key, value| value == nil}
end

def func_find(hash)
    # Check and return the first object that satisfies the property
    # [key, value] pair where the key is an Integer and the value is < 20 
    # or [key, value] pair where the key is a String and the value is a String starting 
    # with the character `a`
    hash.find{|key, value| (key.is_a?(Integer) && value.is_a?(Integer) && value<20)||(key.is_a?(String) && value.is_a?(String) && value.start_with?('a'))}
end