How to Check if an Array Contains a Value in Ruby?

Introduction

Arrays in Ruby are ordered and indexed collections of objects. They can hold various types of elements, including numbers, strings, and even other arrays. To check if an array includes a specific value, Ruby offers multiple methods within its core library.

The include? Method

The include? method is a built-in Ruby method that checks if a ruby array contains a specific value. It returns a boolean value, true if the value is found and false otherwise.

Example

Here's an example:

Explanation

In the code snippet, we define an array called names and utilize the include? method to check if the ruby array contains the values "Virat" and "Rahul". The method outputs true for "Virat" since it exists in the array, while it outputs false for "Rahul" as it is not found within the array.

The member? Method

Similar to include? method, the member? method can also be used to check if a value is present in an array. It behaves exactly like include? and returns a boolean value.

Example

Here's an example:

Explanation

In the code snippet above, we use the member? method to verify whether the names ruby array contains the values "Virat" and "Rahul". The method outputs true for "Virat" as it exists in the array, while it outputs false for "Rahul" since it is not found within the array.

The any? Method

The any? method is a highly adaptable function that checks whether an array has any element that meets a specified condition. It accepts a block or condition as input and returns a boolean output.

Example

Here's an example:

Explanation

In the given code snippet, the any? method is utilized to determine whether the array numbers contains any element that is greater than 3 and any element that is greater than 6. The method returns true for the first case, indicating that there exists at least one element greater than 3 in the array. Conversely, it returns false for the second case, suggesting that no element in the array is greater than 6.

The find? Method

The find? method is utilized to search for the initial element in an array that meets a specific condition. It retrieves the first element that satisfies the condition or returns "nil" if no such element is discovered.

Example

Here's an example:

Explanation

In the above code snippet, we utilize the find? method to search for the first even number in the numbers array and the first number greater than 6. The method returns 2 for the first condition and "nil" for the second condition.

Custom Methods

Why is There a Need to Create a Custom Method?

• Specific Requirements: Sometimes, the built-in methods may not fulfil the specific requirements of our code. Custom methods allow us to tailor the functionality to match our needs precisely.
• Enhanced Readability: Creating custom methods can make our code more readable and maintainable by encapsulating complex logic or repetitive operations within a single method.
• Code Reusability: Custom methods can be reused throughout our codebase, promoting code reusability and reducing redundancy.
• Domain-Specific Logic: In certain domains or industries, we may need to implement specialized algorithms or rules that are not covered by the built-in methods.
• Efficiency Enhancement: Custom methods enhance efficiency by allowing us to implement our logic and utilize different algorithms such as binary search or specialized data structures like tries, to optimize search operations.

How to Create a Custom Method Instead of Using Built-in Methods?

Define a Method: Begin by defining the custom method in our Ruby program. Utilize the def keyword, followed by the method name and any required parameters. Execute the Logic: Include the necessary logic within the method body to perform the desired operations. This may involve returning a specific result, iterating through an array, or checking conditions. Return a Value: The custom method should return a boolean indicating whether the value is present in the array or the intended value itself. Call the Method: Once the custom method is defined, it can be invoked from other parts of our code using its name and the appropriate parameters.

Example

Here's an example of a custom method:

Explanation

The given code snippet includes a custom function called custom_division_check?. This function accepts two arguments: an array, representing the array to be examined, and a value, indicating the multiple to be searched for. Inside the function, there is a loop that iterates over each element of the array using each method. The function immediately returns true if an element divisible by the specified value is found. If the iteration completes without finding a matching element, the function returns false.

In this code snippet, an array named numbers is initialized, containing integers. The custom_division_check? function is called twice: once with the value 3 and once with the value 2. The function accurately determines the presence of a multiple of 3 (9) in the array and returns true. It also correctly identifies the absence of a multiple of 2 and returns false.