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Ruby Array.rassoc(obj) Method
By IncludeHelp Last updated : December 01, 2024
In this article, we will study about Array.rassoc(obj) method. You all must be thinking the method must be doing something which is related to the insertion of a certain element. It is not as simple as it looks. Well, we will figure this out in the rest of our content. We will try to understand it with the help of syntax and demonstrating program codes.
Description and Usage
This method is Public instance method and belongs to the Array class which lives inside the library of Ruby language. This method is used to check whether an object is a part of the particular Array instance or not and that Array instance cannot be a normal Array instance. If it is not normal, it means that Array instance is the Array of multiple Array instances or you can say that it the collection of multiple objects which are itself an object of Array class. Basically, it works for the Array instances whose elements are also Array instances. Let us go through the syntax and demonstrating the program codes of this method.
If you are thinking what it will return then let me tell you, it will return the first contained Array instance where it found the presence of the object. It will return "nil" if it hadn't found the object in any of the Arrays.
Syntax
array_instance.assoc(obj)
Parameters
This method only takes one parameter and that argument is nothing but an object whose presence we want to check.
Example 1
=begin
Ruby program to demonstrate rassoc method
=end
# array declarations
array1 = [1,"Ramesh","Apple",12,true,nil,"Satyam","Harish"]
array2 = ["Akul","Madhu","Ashok","Mukesh",788]
array3 = ["Orange","Banana","Papaya","Apricot","Grapes"]
arraymain = [array1,array2,array3]
puts "Enter the element you want to search"
ele = gets.chomp
if arraymain.rassoc(ele) != nil
puts "Element found in:"
print arraymain.rassoc(ele)
else
puts "Element not found"
end
Output
RUN 1:
Enter the element you want to search
Ramesh
Element found in:
[1, "Ramesh", "Apple", 12, true, nil, "Satyam", "Harish"]
RUN 2:
Enter the element you want to search
Kiwi
Element not found
Explanation
In the above code, you can find that the Array instance on which we have invoked rassoc() method is not any normal Array instance. It is the collection of multiple Array instances. It is returning the whole Array instance where it has found the object inputted by the user.
Example 2
=begin
Ruby program to demonstrate rassoc method
=end
# array declaration
array1 = ["Babita","Sabita","Ashok"]
puts array1.rassoc("Babita")
Output
No Output.
Explanation
In the above, you can verify that rassoc() method does not work upon normal Array instances. It will return nil even if the object is a part of the Array instance.