In Scala, you can check if a hash (a.k.a. map) includes a key using the contains method. Here are some examples:
Example 1: Check if a hash includes a key by specifying the key directly
val myHash = Map("apple" -> 2, "banana" -> 3, "orange" -> 5)
if (myHash.contains("banana")) {
println("The hash includes the key 'banana'")
} else {
println("The hash does not include the key 'banana'")
}
This will output:
The hash includes the key 'banana'
Example 2: Check if a hash includes a key by using a variable
val myHash = Map("apple" -> 2, "banana" -> 3, "orange" -> 5)
val myKey = "grape"
if (myHash.contains(myKey)) {
println(s"The hash includes the key '$myKey'")
} else {
println(s"The hash does not include the key '$myKey'")
}
This will output:
The hash does not include the key 'grape'
Note: You can also use the get method to retrieve the value for a key if it exists in the hash. If the key does not exist, get will return None.
Example 3: Use get to retrieve the value for a key in a hash
val myHash = Map("apple" -> 2, "banana" -> 3, "orange" -> 5)
val myKey = "apple"
val myValue = myHash.get(myKey)
myValue match {
case Some(value) => println(s"The value for key '$myKey' is $value")
case None => println(s"The hash does not include the key '$myKey'")
}
This will output:
The value for key 'apple' is 2