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hashmap

How-to articles, tricks, and solutions about HASHMAP

C# Java HashMap equivalent

In Java, the HashMap class is the equivalent of the Dictionary class in C#. It is a map data structure that stores (key, value) pairs and provides fast lookup and insertion of elements.

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get string value from HashMap depending on key name

To get the string value from a HashMap depending on the key name in Java, you can use the get() method of the Map interface.

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HashMap - getting First Key value

To get the first key-value pair from a HashMap in Java, you can use the entrySet() method to get a set of the map's entries and then use the iterator() method to get an iterator for the set.

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How can I sort Map values by key in Java?

To sort the values of a Map by key in Java, you can use the TreeMap class, which is a Map implementation that maintains its entries in ascending key order.

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How to convert List to Map?

To convert a List to a Map in Java, you can use the stream() method and the collect() method along with a Collectors.toMap() call. Here's an example of how to do this:

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How to get values and keys from HashMap?

To get the values and keys from a HashMap in Java, you can use the values and keySet methods.

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How to sort a HashMap in Java

To sort a HashMap in Java, you can use the TreeMap class, which is a Map implementation that maintains its entries in ascending order, sorted according to the keys.

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How to update a value, given a key in a hashmap?

To update the value associated with a key in a HashMap in Java, you can use the put() method.

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Is there Java HashMap equivalent in PHP?

In PHP, the equivalent to a Java HashMap would be an associative array.

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Iterate through a HashMap

There are several ways to iterate through a HashMap in Java: Using the for-each loop

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Java Compare Two Lists

To compare two lists in Java, you can use the equals() method of the List interface.

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Java Hashmap: How to get key from value?

To get the key for a given value in a java.util.HashMap, you can use the entrySet() method of the java.util.HashMap class to get a set of the mappings in the map, and then iterate over the set and check the value of each mapping.

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Key existence check in HashMap

To check if a key exists in a HashMap in Java, you can use the containsKey method.

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Sorting HashMap by values

To sort a HashMap by values in Java, you can use the Map.Entry interface and the Comparator interface to create a comparator that compares the values in the map.

java hashmap sorting

What are the differences between a HashMap and a Hashtable in Java?

There are several differences between a HashMap and a Hashtable in Java:Synchronization: Hashtable is synchronized, while HashMap is not.

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