To get the value of a key in a hash (also known as a map) in Scala, you can use the apply method or the getOrElse method. Here are examples of each:
Using the apply method:
val map = Map("key1" -> "value1", "key2" -> "value2")
val value1Option = map.get("key1") // Retrieves the value of key1 as an Option
val value1 = map("key1") // Retrieves the value of key1 using the apply method
Using the getOrElse method:
val map = Map("key1" -> "value1", "key2" -> "value2")
val value1 = map.getOrElse("key1", "default") // Retrieves the value of key1 with a default value if it doesn't exist in the map
val value3 = map.getOrElse("key3", "default") // Retrieves the value of key3 with a default value because it doesn't exist in the map
Using the apply method will throw an exception if the key doesn't exist in the map, while using the getOrElse method will return a default value if the key doesn't exist in the map.