How to get values and keys from HashMap

Question

I m writing a simple edit text in Java  When the user opens it  a file will be opened in JTabbedPane  I did the following to save the files opened   HashMap lt String  Tab gt  hash   new HashMap lt String  Tab gt      Where Tab will receive the values  such as  File file  JTextArea container  JTabbedPane tab   I have a class called Tab   public Tab File file  JTextArea container  JTabbedPane tab        this file   file      this container   container      this tab   tab      tab add file getName    container       readFile        Now  in this SaveFile class  I need get the Tab values stored in the HashMap  How can I do that

User · Answer

You have to follow the following sequence of opeartions    Convert Map to MapSet with  map entrySet    Get the iterator with Mapset iterator    Get Map Entry with iterator next    use Entry getKey   and Entry getValue         define Map for  Map Entry entry  map entrySet      System out println entry getKey     entry getValue

User · Answer

Map is internally made up of Map Entry objects  Each Entry contains key and value  To get key and value from the entry you use accessor and modifier methods    If you want to get values with given key  use get   method and to insert value  use put   method    Define and initialize map  Map map   new HashMap    map put  USA  1  map put  Japan  3  map put  China  2  map put  India  5  map put  Germany  4   map get  Germany      returns 4   If you want to get the set of keys from map  you can use keySet   method  Set keys   map keySet    System out println  All keys are      keys      To get all key  value for String key  keys       System out println key          map get key        Generally  To get all keys and values from the map  you have to follow the sequence in the following order    Convert Hashmap to MapSet to get set of entries in Map with entryset   method   Set st   map entrySet    Get the iterator of this set  Iterator it   st iterator    Get Map Entry from the iterator  Map Entry entry   it next    use getKey   and getValue   methods of the Map Entry to get keys and values       Now access it Set st    Set  map entrySet    Iterator it   st iterator    while it hasNext         Map Entry entry   mapIterator next        System out print entry getKey             entry getValue         In short  use iterator directly in for  for Map Entry entry map entrySet         System out print entry getKey             entry getValue

User · Answer

To get all the values from a map   for  Tab tab   hash values             do something with tab     To get all the entries from a map   for   Map Entry lt String  Tab gt  entry   hash entrySet          String key   entry getKey        Tab tab   entry getValue           do something with key and or tab     Java 8 update   To process all values   hash values   forEach tab - gt     do something with tab        To process all entries   hash forEach  key  tab  - gt     do something with key and tab

User · Answer

You could use iterator to do that    For keys    for  Iterator  lt tab gt  itr  hash keySet   iterator    itr hasNext              use itr next   to get the key value     You can use iterator similarly with values

User · Answer

for  Map Entry lt String  Tab gt  entry   hash entrySet          String key   entry getKey        Tab tab   entry getValue           do something with key and or tab     Works like a charm

User · Answer

It will work with hash get  key    Where key is your key for getting the value from Map

User · Answer

Use the  string  key of the hashmap  to access its value which is your tab class   Tab mytab   hash get  your string key used to insert

User · Answer

You give 1 Dollar  it gives you a cheese burger  You give the String and it gives you the Tab  Use the GET method of HashMap to get what you want    HashMap get  String

User · Answer

With java8 streaming API   List values   map entrySet   stream   map Map Entry  getValue  collect Collectors toList

User · Answer

To get values and keys you could just use the methods values   and keySet   of HashMap      public static List getValues Map map        return new ArrayList map values        public static List getKeys Map map        return new ArrayList map keySet

[java] How to get values and keys from HashMap?

Examples related to java

Examples related to hashmap