Ruby Find Elements in an Array

Need of Finding Element in an Array

The need to find an element in an array is essential for various tasks such as:-

• Accessing Specific Data
   
• Filtering and Selecting Elements
   
• Determining Indexes or Positions
   
• Quickly and Efficiently Accessing Array Elements
   
• Manipulating Array Elements
   
• Making good programming decisions
   

Different Methods to Find Elements in an Array

In this section, "Ruby find elements in an array," we will see different methods to find elements in an array.

Include Method

The include method in Ruby programming checks whether the specific element is present in the given array. If the element is present in an array, it returns true; otherwise, it will return false.

The include method is used to make the code simplified and clean to check for the presence of elements.

Example

vehicle = ["Car", "Truck", "Bus", "Cycle"]
puts vehicle.include?("Bus")  
puts vehicle.include?("Boat")  

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Output

Explanation

In the above example, include method checks for “bus” and “boat” in the vehicle array, it returns true since “Bus” is present in the array whereas false for “Boat” which is not present in the array.

Index Method

The index method in Ruby is used to find the index of the first occurrence of the specified element in an array. If no element is found in an array, it will return nil. Otherwise, it will return the index of the fixed element.

It will be used when further operation based on the element position index is required, such as handling duplicate elements in an array. 

Example

num = [5,4,3,6,7]
puts num.index(6)  
puts num.index(9)  

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Output

Explanation

In the above example, the index method returns an index of 6, whereas it returns nil for 9.

Select Method

The select method in Ruby is used to create a new array from the old array, which contains elements based on the specified condition. It contains only that elements in a new array by iterating an old array whose specific condition is true.

It is used to create a subset of an element based on a specific condition. It filters the elements very fastly and powerfully.

Example

names = ["ram", "shyam", "mohit", "akash", "shubham"]
nam = names.select { |name| name.length > 4 }
puts nam  

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Output

Explanation

In the above example, the select method returns the elements of the array whose length is greater than 4. So, except “ram”, it returns all the elements.

Find Method

The find method in the context of "Ruby find elements in an array" returns the first element that satisfies the specific condition. It iterates over an array, stops when specific conditions are met, and returns that first element. If no element is found, it returns nil.

It is used to find the desired element quickly based on the specific condition.

Example

fruits = ["mango", "banana", "papaya", "pineapple"]
search = fruits.find { |fruit| fruit.length > 6}
puts search  

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Output

Explanation

In the above example, the find method returns the “pineapple” since it is the first element whose length is greater than 6.

Find_index Method

The find_index method in the context of "Ruby find elements in an array" is used to find the index of the first occurrence of an element in an array that satisfies the specific condition. It returns the first element that satisfies the condition by iterating through the array. Otherwise, it will return nil.

Example

nums = [11, 22, 33, 44, 55, 66, 77, 88, 99, 110]
ind = nums.find_index { |number| number > 77 }
puts ind 

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Output

Explanation

In the above example, the find_index method returns the index of 88, which is 7 since it is the first element greater than 77.

The difference between the find_index and the index method is that the find_index method returns the index of the first element that satisfies the specific condition. In contrast, the index method returns the index of a first element without any condition.

Reject Method

The reject method in Ruby is used to create a new array from an old array that excludes an element that satisfies the specific condition. It returns an array containing elements that do not satisfy the particular condition. It returns the array that excludes an element you do not want.

Example

nums = [1, 2, 3, 4, 5, 6, 7, 8, 9, 10]
even_num = nums.reject { |num| num.odd? }
puts even_num 

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Output

Explanation

In the above example, the reject method filters the odd number present in an element.

Frequently Asked Questions

How to determine the index of every instance of a given element in an array?

Using the ‘each_with_index’ function to loop through the array and ‘select’ to filter items that match the target element to get the indices of each occurrence of a specific element in an array.

What is the best way to locate an element based on a condition or predicate?

The ‘find’ or ‘detect’ method on the array, supplying a block that describes the condition or predicate, is the best technique to discover an element based on a condition or predicate.

How to search an array for a specific element that appears several times?

To search an array for a particular element that appears several times use the find_all or select method, passing a block that checks for equality with the desired element.

What procedure is used to find every element in an array that meets a particular criterion?

One can use the Array_select method, which generates a new array from the old array of items containing just those elements that match the predicate or condition supplied in an array.

Conclusion

Ruby's array manipulation techniques make this work more accessible, saving time and effort in the process. In this blog, we have discussed Ruby finds elements in an array using different in-built methods and functions.

Do not stop learning! We recommend you read some articles related to Ruby Find Elements in an Array: 

•  Array in Ruby
•  Array and Hash Access with []
•  Collection in Ruby

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