How to sort a HashMap in ascending order [duplicate]

Question

I have the following Key : Value pairs.

A56:A64=9, A65:A73=9, A2:A8=7, A49:A55=7, A20:A26=7, A9:A19=11, A43:A48=6, A27:A42=16

I want to sort them in an ascending order. I tried using a TreeMap but a got this :

{A20:A26=7, A27:A42=16, A2:A8=7, A43:A48=6, A49:A55=7, A56:A64=9, A65:A73=9, A9:A19=11}

A2:A8=7 should be first, but it is coming third.

Please let me know how I can fix this.

Hemingway

"ascending order" of what? Key, values? – Creditor

Please show your code. – Templet

you can use Collections.sort with a comparator. so you can decide how it will compare – Brasil

Default comparator sorts strings in lexicographical order. What you need is called numerical order. Check out the link in my previous comment if you want to implement custom comparator for hashmap – Ginaginder

I want in ascending order of Keys – Hemingway

Answer 1

TreeMap for a String key would use String lexicographical order by default (that's the natural ordering for Strings), unless you supply your own Comparator in the constructor.

A2:A8 comes after A20:A26 when using lexicographical order.

Your comparator would probably have to split the String key into 4 parts (for example, A20:A26 would be split to A, 20, A and 26) and compare each pair of parts separately, using integer comparison for the integer parts.

Shanta

I splited the key on ":" then took the first parameter and replaced the "A", which gave me numeric value and normal TreeMap worked there.thanks – Hemingway