I am new in Java, and trying to understand Nested Maps, exactly how I can filter unnecessary result from loop.
Map<String,Map<Integer,Integer>> add = new LinkedHashMap<>();
Map<Integer,Integer> add2 = new LinkedHashMap<>();
for(Map.Entry<String,Map<Integer,Integer>> view: add.entrySet()){
System.out.println("Name: " + view.getKey());
for(Map.Entry<Integer,Integer>view2: add2.entrySet()){
System.out.println("Number: "+ view2.getKey());
System.out.println("ID:"+ view2.getValue());
System.out.println("==================");
}
}
The result with:Name1,1234 and Name2,2345 is:
Name: Name1
Number: 1234
ID:1
Number: 2345
ID:2
====================
Name: Name2
Number: 1234
ID:1
Number: 2345
ID:2
I want only result for: name 1, number 1, ID1 without Number2 and ID2 on first loop... Or how to iterate this without double number and ID?
--> When i put 3 Names, with 3 numbers for each one name, for the first One i get:
Name: name1
Number: 111
ID:1
===============
Number: 2222
ID:2
===============
Number: 3333
ID:3
===============
and for others is the same
Name: name2
Number: 111
ID:1
===============
Number: 2222
ID:2
===============
Number: 3333
ID:3
===============
should be just
Name 1
Number: 111
ID:1
============
Name 2
Number: 222
ID:2
============
Name 3
Number: 333
ID:3
This is how you iterate over a nested Map
:
Map<String,Map<Integer,Integer>> add = new LinkedHashMap<>();
for(String key : add.keySet()) {
for(Integer key : add.get(key).keySet()) {
// your code here
}
}
You missed the add.get(key).keySet()
part in your code.
to know about iterating nested map read this A better way to iterate java maps
You can iterate over the keys in a map using the Map.keySet() method. Also go through this link.
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