Ruby Enumerable detect() Method

Syntax

The syntax for the Ruby detect() method is as follows:

Parameters

The detect() function accepts as a parameter a block containing the condition to be checked for each element in the enumerable.

Return Value

The detect() function returns the first enumerable element that meets the supplied criterion. If no element meets the criteria, nil is returned.

Exception

The detect() function throws no exceptions.

Basic Usage of detect method in Ruby

The detect() function in Ruby is a useful tool for quickly locating a specific element within an array or hash. Whether working with arrays or hashes, this approach is helpful, providing an easy and elegant solution to identify required components without the need for complicated iteration.

We can specify a criterion that the desired element must fulfill, and the method will iterate over the collection to locate the first member that meets the specified criteria. This avoids the need to write numerous loops or conditional statements to manually do the search.

Using the detect method

Using with a Lambda

We can also use a lambda or a proc as the condition in the detect() method. This gives us more flexibility and allows us to define custom conditions. Let's see an example:

Output

Explanation

In this example, we define a lambda is_multiple_of_three that checks if a number is divisible by three. We then pass this lambda as the condition to the detect() method, which returns the first element (3) that satisfies the condition.

Using with a Hash

The detect() method can also be used with hashes. In this case, it operates on the values of the hash rather than the keys. Let's consider an example where we have a hash of cities and their populations, and we want to find the first city with a population greater than 25000.

Output

Explanation

In this example, the detect() method returns the first key-value pair in the cities hash where the population is greater than 25000.

Using with Regular Expressions

The detect() method can also be used with regular expressions. It allows us to find the first element in an enumerable that matches a specific pattern. Let's see an example:

Output

Explanation

In this example, the detect() method returns the first name in the names array that contains the letter "b".

Examples

Example 1

Let's start with a basic array example. Let's assume we have an integer array and we wish to locate the first even integer in the array:

Output

Explanation

In this example, the detect() function loops through the numbers array, returning the first value (2) that meets the requirement num.even?.

Example 2

Now, let's see an example of using detect method on an array of strings:

Output

Explanation

In this example, the detect() method loops through the names array and returns the first string that meets the requirement name.length > 5. The name "Shubman" has a length greater than 5, so it is returned as the result.