How do you create a dictionary in Java?
JavaDictionaryKey ValueJava Problem Overview
I am trying to implement a dictionary (as in the physical book). I have a list of words and their meanings.
What data structure / type does Java provide to store a list of words and their meanings as key/value pairs.
How, given a key, can I find and return the value?
Java Solutions
Solution 1 - Java
You'll want a Map<String, String>
. Classes that implement the Map
interface include (but are not limited to):
Each is designed/optimized for certain situations (go to their respective docs for more info). HashMap
is probably the most common; the go-to default.
For example (using a HashMap
):
Map<String, String> map = new HashMap<String, String>();
map.put("dog", "type of animal");
System.out.println(map.get("dog"));
type of animal
Solution 2 - Java
This creates dictionary of text (string):
Map<String, String> dictionary = new HashMap<String, String>();
you then use it as a:
dictionary.put("key", "value");
String value = dictionary.get("key");
> Works but gives an error you need to keep the constructor class same as the declaration class. I know it inherits from the parent class but, unfortunately it gives an error on runtime.
Map<String, String> dictionary = new Map<String, String>();
This works properly.
Solution 3 - Java
Use Map interface and an implementation like HashMap
Solution 4 - Java
There's an Abstract Class Dictionary
http://docs.oracle.com/javase/6/docs/api/java/util/Dictionary.html
However this requires implementation.
Java gives us a nice implementation called a Hashtable
http://docs.oracle.com/javase/6/docs/api/java/util/Hashtable.html