Top "Hashmap" questions

Difference between hash_map and unordered_map?

I recently discovered that the implementation of the hash map in C++ will be called unordered_map. When I looked …

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Building ordered JSON String from LinkedHashMap

I had a need for having Key/Value pairs in the order of my insertion, so I opted to use …

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Java - Write hashmap to a csv file

I have a hashmap with a String key and String value. It contains a large number of keys and their …

java csv hashmap supercsv

How to correctly use HashMap?

HashMap savedStuff = new HashMap(); savedStuff.put("symbol", this.symbol); //this is a string savedStuff.put("index", this.index); //this is …

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Collectors.groupingBy doesn't accept null keys

In Java 8, this works: Stream<Class> stream = Stream.of(ArrayList.class); HashMap<Class, List<Class>&…

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Java Pass By Value and Pass By Reference

i have done the following sample with to check my knowledge import java.util.Map; public class HashMap { public static …

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Using java.util.Map in h:dataTable

I need to display Map using <h:dataTable>. My backing bean has a Map property as below: public …

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Why hashmap lookup is O(1) i.e. constant time?

If we look from Java perspective then we can say that hashmap lookup takes constant time. But what about internal …

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What are hashtables and hashmaps and their typical use cases?

I have recently run across these terms few times but I am quite confused how they work and when they …

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Scrapy Crawl URLs in Order

So, my problem is relatively simple. I have one spider crawling multiple sites, and I need it to return the …

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