Steps

1. How to initialize a Sequence of donuts

The code below shows how to initialize a Sequence of Donut elements of type String.

println("Step 1: How to initialize a Sequence of donuts")
val donuts: Seq[String] = Seq("Plain Donut", "Strawberry Donut", "Glazed Donut")
println(s"Elements of donuts = $donuts")

You should see the following output when you run your Scala application in IntelliJ:

Step 1: How to initialize a Sequence of donuts
Elements of donuts = List(Plain Donut, Strawberry Donut, Glazed Donut)

2. How to check if a particular element exists in the sequence using the exists function

The code below shows how to use the exists method to find if a particular element exists in a sequence - more precisely if donut element Plain Donut exists in the donut sequence.

println("\nStep 2: How to check if a particular element exists in the sequence using the exists function")
val doesPlainDonutExists: Boolean = donuts.exists(donutName => donutName == "Plain Donut")
println(s"Does Plain Donut exists = $doesPlainDonutExists")

You should see the following output when you run your Scala application in IntelliJ:

Step 2: How to check if a particular element exists in the sequence using the exists function
Does Plain Donut exists = true

3. How to declare a predicate value function for the exists function

The code below shows how to declare a predicate value function to find if a Plain Donut element exists in a sequence.

println("\nStep 3: How to declare a predicate value function for the exists function")
val plainDonutPredicate: (String) => Boolean = (donutName) => donutName == "Plain Donut"
println(s"Value function plainDonutPredicate = $plainDonutPredicate")

You should see the following output when you run your Scala application in IntelliJ:

Step 3: How to declare a predicate value function for the exists function
Value function plainDonutPredicate = <function1>

NOTE:

• The predicate function is a Value Function.

4. How to find element Plain Donut using the exists function and passing through the predicate function from Step 3

The code below shows how to call the exists method and pass-through the value predicate function from Step 3 to find if a Plain Donut element exists in the donut sequence.

println("\nStep 4: How to find element Plain Donut using the exists function and passing through the predicate function from Step 3")
println(s"Does Plain Donut exists = ${donuts.exists(plainDonutPredicate)}")

You should see the following output when you run your Scala application in IntelliJ:

Step 4: How to find element Plain Donut using the exists function and passing through the predicate function from Step 3
Does Plain Donut exists = true

5.How to declare a predicate def function for the exists function

The code below shows how to a predicate def function to find if a Plain Donut element exists in a sequence.

println("\nStep 5: How to declare a predicate def function for the exists function")
def plainDonutPredicateFunction(donutName: String): Boolean = donutName == "Plain Donut"

6. How to find element Plain Donut using the exists function and passing through the predicate def function from Step 5

The code below shows how to call the exists method and pass-through the def predicate function from Step 5 to find if a Plain Donut element exists in the donut sequence.

println("\nStep 6: How to find element Plain Donut using the exists function and passing through the predicate function from Step 5")
println(s"Does plain Donut exists = ${donuts.exists(plainDonutPredicateFunction(_))}")

You should see the following output when you run your Scala application in IntelliJ:

Step 6: How to find element Plain Donut using the exists function and passing through the predicate function from Step 5
Does plain Donut exists = true