How can I divide HashMap

Question

Here is the code:

HashMap<String, Integer> arr = new HashMap<String, Integer>(); 
arr.put("one", 1); 
arr.put("two", 2); 
arr.put("three", 3);

how can I to get all strings as String[] array and all integers as Int[] array?

thanks to all! all is correct, if somebody has the same Problemm, answer is:

String[] entry =(String[])arr.keySet().toArray(new String[arr.size()]);
Integer[] entry_values =(Integer[])arr.values().toArray(new Integer[arr.size()]);

see: http://stackoverflow.com/questions/3293946/the-easiest-way-to-transform-collection-to-array — Florian Groetzner, Nov 15 '13 at 10:15
and get the keys by i think the command is .keySet() and values by calling values() but im not sure if the commands are exactly that — Florian Groetzner, Nov 15 '13 at 10:15
Check this thread http://stackoverflow.com/questions/12960265/retrieve-all-values-from-hashmap-keys-in-an-arraylist-java — Ende Neu, Nov 15 '13 at 10:16
if you would have googled it, you would have had thousands results on this, and this is not even related to android. No offence. — Vedang Jadhav, Nov 15 '13 at 10:19

Evgeniy Dorofeev · Answer 1 · 2013-11-15T10:17:22.753

2

1) arr.keySet().toArray(new String[arr.size()]);

2) arr.values().toArray(new Integer[arr.size()]);

edited Nov 15 '13 at 10:17

answered Nov 15 '13 at 10:15

Evgeniy Dorofeev

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score 1 · Answer 2 · answered Nov 15 '13 at 10:15

1

You can use the keySet() and values() methods to get the strings and integers alone. They both return collections, so you can then call toArray on them.

answered Nov 15 '13 at 10:15

Roland Illig

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Simulant · Answer 3 · 2013-11-15T10:49:47.390

1

There is no Method to get your Items by their type, but by their function in the map.

HashMap<String, Integer> arr = new HashMap<String, Integer>();     
Set<String> keys = arr.keySet(); // all keys.
Collection<Integer> values = arr.values(); //all values.

you can call toArray() on both of your results. Add a new Array as argument to define the type of the result.

String[] strings = keys.toArray(new String[arr.size()]);
Integer[] ints = values.toArray(new Integer[arr.size()]);

edited Nov 15 '13 at 10:49

answered Nov 15 '13 at 10:16

Simulant

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by String[] strings = keys.toArray(new String[]); have I a Error java: array dimension missing – user2995801 Nov 15 '13 at 10:45
you can add any size, if the size is to small a new array with the right dimension is created. Adding the right dimension saves this operation. – Simulant Nov 15 '13 at 10:50

score 0 · Answer 4 · answered Nov 15 '13 at 10:20

0

Try this out:

String strArr[] = new String[arr.size()];
arr.keySet().toArray(strArr); // Populate the String array with map keys

Integer intArr[] = new Integer[arr.size()];
arr.values().toArray(intArr); // Populate the Int array with map values

answered Nov 15 '13 at 10:20

Ankur Shanbhag

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How can I divide HashMap

4 Answers4