How can I convert a String into a HashMap? into Where the keys are first_name, last_name and gender and the values are naresh, kumar, male. Note: Keys can be any thing like city = hyderabad. I am looking for a generic approach. Answer This is one solution. If you want to make it more generic, you can use the StringUtils
Tag: hashmap
Can an array be used as a HashMap key?
If a HashMap’s key is a String[] array: Can you access the map by using a newly created String[] array, or does it have to be the same String[] object? Answer It will have to be the same object. A HashMap compares keys using equals() and two arrays in Java are equal only if they are the same object. If
HashMap value auto increment
when I was coding, one question occurred to me, which is if the value part(Integer) in the HashMap is able to auto-increment in the following scenario? Answer Consider using an AtomicInteger: Also consider using a for loop to simplify the code.
Does HashMap.clear() resize inner hash table to the original size?
What happens to the HashMap after this code execution? HashMap m = new HashMap(); for (int i = 0; i < 1024 * 1024; i++) m.put(i, i); m.clear(); After 1M puts the inner hash table will grow …
How to create a HashMap with two keys (Key-Pair, Value)?
I have a 2D array of Integers. I want them to be put into a HashMap. But I want to access the elements from the HashMap based on Array Index. Something like: For A[2][5], map.get(2,5) which returns a value associated with that key. But how do I create a hashMap with a pair of keys? Or in general, multiple keys:
How to print all key and values from HashMap in Android?
I am trying to use HashMap in Android sample project. Now, am doing sample project for learn android. I just store keys and values in HashMap, i want to show the keys and their values in EditView. I followed below code in my sample project. But, first key and value only printing in EditView. In EditView iOS = 100 is
How to calculate HashMap memory usage in Java?
I was asked in an interview to calculate the memory usage for HashMap and how much estimated memory it will consume if you have 2 million items in it. For example: The mapping is like this. How would I estimate the memory usage of this HashMap Object in Java? Answer The short answer To find out how large an object
Shortcut for adding to List in a HashMap
I often have a need to take a list of objects and group them into a Map based on a value contained in the object. Eg. take a list of Users and group by Country. My code for this usually looks like: However I can’t help thinking that this is awkward and some guru has a better approach. The closest
C# Java HashMap equivalent
Coming from a Java world into a C# one is there a HashMap equivalent? If not what would you recommend? Answer Dictionary is probably the closest. System.Collections.Generic.Dictionary implements the System.Collections.Generic.IDictionary interface (which is similar to Java’s Map interface). Some notable differences that you should be aware of: Adding/Getting items Java’s HashMap has the put and get methods for setting/getting items