Java associative-array

Java doesn’t support associative arrays, however this could easily be achieved using a Map. E.g., Even more accurate to your example (since you can replace String with any object that meet your needs) would be to declare: See the official documentation for more information

What is the best way to convert an array to a hash in Ruby

NOTE: For a concise and efficient solution, please see Marc-André Lafortune’s answer below. This answer was originally offered as an alternative to approaches using flatten, which were the most highly upvoted at the time of writing. I should have clarified that I didn’t intend to present this example as a best practice or an efficient … Read more

What is a hash function in java?

The Wikipedia article will have a lot of technical information, but a simplistic view of hashing is something like the following. Imagine that there’s a magical function that can give a number to any object. Given the same object, it always return the same number. Immediately now you have a quick way to test if … Read more

Array to Hash Ruby

That’s it. The * is called the splat operator. One caveat per @Mike Lewis (in the comments): “Be very careful with this. Ruby expands splats on the stack. If you do this with a large dataset, expect to blow out your stack.” So, for most general use cases this method is great, but use a … Read more

Printing a java map Map – How?

I’m sure there’s some nice library that does this sort of thing already for you… But to just stick with the approach you’re already going with, Map#entrySet gives you a combined Object with the key and the value. So something like: will do what you’re after. If you’re using java 8, there’s also the new streaming approach.

What is a hash function in java?

The Wikipedia article will have a lot of technical information, but a simplistic view of hashing is something like the following. Imagine that there’s a magical function that can give a number to any object. Given the same object, it always return the same number. Immediately now you have a quick way to test if … Read more

Implementing a HashMap in C

Well if you know the basics behind them, it shouldn’t be too hard. Generally you create an array called “buckets” that contain the key and value, with an optional pointer to create a linked list. When you access the hash table with a key, you process the key with a custom hash function which will … Read more