import java.util.*; public class Main{ public static void main(String args[]) { // Hashtable = A data structure that stores unique keys to values ex. // Each key/value pair is known as an Entry // FAST insertion, look up, deletion of key/value pairs // Not ideal for small data sets, great with large data sets // hashing = Takes a key and computes an integer (formula will vary based on key & data type) // In a Hashtable, we use the hash % capacity to calculate an index number // key.hashCode() % capacity = index // bucket = an indexed storage location for one or more Entries // can store multiple Entries in case of a collision (linked similarly a LinkedList) // collision = hash function generates the same index for more than one key // less collisions = more efficiency // Runtime complexity: Best Case O(1) // Worst Case O(n) Hashtable table = new Hashtable(10); table.put(100, "Spongebob"); table.put(123, "Patrick"); table.put(321, "Sandy"); table.put(555, "Squidward"); table.put(777, "Gary"); for(Integer key : table.keySet()) { System.out.println(key.hashCode() % 10 + "\t" + key + "\t" + table.get(key)); } } }

@54peace

2 жыл бұрын

more python tutorials please bro🙏

@ashutoshsoni9723

2 жыл бұрын

Bro can you please make a video on Library Management System in JAVA. It's my request please!

@masternobody1896

2 жыл бұрын

nice

@joyceasante8292

Жыл бұрын

import java.util.*; public class Main { public static void main(String[] args) { Hashtabletable = new Hashtable(10); table.put(254,"Irene"); table.put(802,"Derrek"); table.put(671,"Alonso"); table.put(545,"Veronica"); //System.out.println(table.get(545)); //table.remove(671); for(Integer key : table.keySet()){ //System.out.println(key + "\t" + table.get(key)); System.out.println(key.hashCode() % 10 + "\t" + key + "\t" + table.get(key)); } } } _____________________________________________ import java.util.*; public class Main { public static void main(String[] args) { Hashtabletable = new Hashtable(10); table.put("254","Irene"); table.put("802","Derrek"); table.put("671","Alonso"); table.put("545","Veronica"); //table.remove(671); for(String key : table.keySet()){ //System.out.println(key.hashCode() + "\t" + key + "\t" + table.get(key)); //System.out.println(key.hashCode() % 10 + "\t" + key + "\t" + table.get(key)); //System.out.println(key.hashCode() % 11 + "\t" + key + "\t" + table.get(key)); System.out.println(key.hashCode() % 21 + "\t" + key + "\t" + table.get(key)); } } }

@pavanimaddala8060

Жыл бұрын

Can you explain how to create hash table in mysql

Was a programmer on a statewide court system back in the late 80's that needed a surname search to return a full page of results in less than a second. We used hashing tables and progressive searches to keep the speed amazingly fast. I think we had it down to about 0.2 of a second. They are fantastic with really large collections of data that needs searching.

Hey Bro, I just wanna thank you for teaching me all this stuff. 7 months ago I was almost nowhere not even knowing how to write a main method in Java but now I'm programming my own graphics library. You're truly a legend😎

@blu5175

2 жыл бұрын

whats a graphic library im new sorry

@Proletariat-intifada

Жыл бұрын

@@blu5175 libraries in java are a series of already build methods that you can use. For example, whenever you want to write something in the java console you need to import the java.util.Scanner library. My guess is that this guy is talking about a library to build a 3d engine with java

@blu5175

Жыл бұрын

@@Proletariat-intifada Yea I learnt this by now it's been 11 months! Haha but still thank you very much?

@AMZ_official

8 ай бұрын

@@blu5175 It's been 11 months again! did you complete it? What else have you achieved in your career? Asking for just motivation

@RonnieBanerjee007

Ай бұрын

​@@Proletariat-intifada well, you tried to help, that's what counts ❤

Bro, We just started going through Hash Tables in our CompSci class and now you release a video. Thank you!

that actually makes so much sense!! was looking at the profssors notes and watching his lectures and not understanding it one single bit!!!! long live the BRO!!!!

Level of teaching of Bro is just on another level👍

Simple and understandable. Thank you so much for this tutorial!

Wow, this is a really good introduction to hash tables!

@BroCodez

2 жыл бұрын

thanks Grayson!

@deepakr1945

Жыл бұрын

@@BroCodez it bad

@elielvieira3041

Жыл бұрын

@@deepakr1945 nah

@windigo77

6 ай бұрын

It's too bad it violates the ADA with its use of camelCase for method names, and is therefore an illegal language to use in the workplace

This was a very insightful video, thanks a lot. Although I really wished you also went over how to treat a bucket as a linked list and iterate through it to find the key you're looking for.

Oh My Goodness... The best video on HashMap data structure. You're the man! 👍

Thank you, I have been having questions on HashTable and wanted to understand hashCode, excellent explanation, keep doing more videos.

I am surprised my computer science curriculum barely even mentioned hash tables. They have been such a game changer to me at work as a software engineer. Way faster and easier than using an array and nested loops.

@dispatch-indirect9206

11 ай бұрын

_I am surprised my computer science curriculum barely even mentioned hash tables_ From interviewing people, this seems like fairly common practice in CS. But chasing buzzwords is devaluing CS: these fundamentals are what distinguished a four-year degree from a coding bootcamp.

@randomrun1

6 ай бұрын

That's interesting, I'm about to start my BSCS and I'm pregaming with the popular Java MOOC. It has an explanation of how to use hash tables in the 8th week and how to make them from scratch in the 12th week. Glad I got the info there if it's not going to be in my curriculum.

Simply, subtly & nearly explained Bro Sir 👌🏼 #KeelItUp ✌🏼 #LoveFromINDIA🇮🇳

As always, an excellent presentation. thank you

This is a great video, thank you. It's much clearer than my course material.

Bro, you Rock. Best and simple explanation of Hash tables. Thanks

very nice tutorial. BIG LIKE

Brooo!!!!....you just explain so good!....got it just by watching it once!

thank you for this tutorial, now i can finally understand the HashTable.

Things to note: If you have collisions the best course of action is to change your hash function. In your example, a good hash function would be taking the ascii code of the rightmost number and subtracting 48, that way you'd have 0 collisions and don't need to do % anymore. Another thing, if your table size is a power of 2 you don't have to do % anymore, you can instead do bitwise and with table size.

@mikoalt

6 ай бұрын

Can you explain the bitwise with table size if the power is 2?

@ThomasEdits

5 ай бұрын

I just found out about hashtables so I would appreciate some input: If you are using a hashtable for storing dynamic data, how would you know what hash function always guarantees no collisions?

@hwstar9416

5 ай бұрын

@@ThomasEdits your data is never truly random. You can always make your hash function avoid collisions (not always completely) by analyzing your data and coming up with a good hash

I didn't pay attention during lecture and I have a quiz tomorrow, so this is a lifesaver!

i didn't understand the other videos but you clearly explained how it works, thanks for the content

This video is amazingly helpful

I studied this last term but didn't understand what I do now. Thank you.

It’s beautiful lecture I like this hash , I’m always favourite your lecture bro due to your best explanation , keep going bro

Thanks! love your videos!

Very nice lesson, like every other!

Wow thank you so much, this was super clear!!!!

Unbelievably good video

Thanks a lot for providing a valuable video.

Good explanation . Liked it a lot !

thank you sir , best explanation.

Really good, no babbling, just information.

I love this channel so, so much

good surface level info

Nice explanation 👍

The best video I've seen today ❤

top quality content. great job, Bro!

The BRO is BACK!

I love that man. Thanks mate

Bro is an absolute legend

bro you are insane Thanks sir I really appreciate

good quality content!

what do you call when u give that type of solution in collision, is it open hashing or not?

Nice, can you make a video on suppliers and consumers next?

Thanks for this videos Bro!

Well done, TY!

Thank you so much sir.

Wow! Nice.

Does google uses hash tables to display instant results ?

Could you go over the A star algorithm next pls

thanks bro... greetings from Ecuador

I love youuu🥺🥺 Respectfully BUT sincerely Many thanks!

Is it possible to design the table to have a dynamic capacity that can be adjusted if there are collisions?

@kylebelle246

5 күн бұрын

i could see this taking more work and end up being slower than just appending to the linked list, since you the existing element now also need to be moved since their table index may no longer be the same give the remainder will likely be different. i would say just make sure the hashtable is sized appropriately and at that point you've done the best you could

Bro thx for the free videos. How can I apply this topic in real life maybe in GUI?

helpful, thank you

you are the best

hi is it possible to implement the hash table using an array?

Thank you for this video

I thought I understood what a hash table was till I saw this video 🙏

THANK YOU YOU SAVED ME

how we can deal with HashTable of Classes? Like in place of int and string key it is some sort of class. Like Hashtable;

Nice video!

Keep going ❤

tooo cool man

thank you bro. Student from Poland :>

@Bro code, it would be great if you teach android development with kotlin also...

Thank you!

Eyyo Brooooo you are a legend!!!

Hash table is my favoriate data structure😉

Good work👍👍👍👍

Sir , please provide use app development course , It's a very helpful .

I learn how to use hash table without tutorial now :)

Thank you Bro!

Do you have a patreon or paypal for us to donate?

nice vid man thanks

Bro can you please do assembler tutorial videos?

Wow 👍👍

Ok, but the bucket we're talking about is a memory address? I mean, if we have a collision, we must create a linked list. Fine with that I get it, but that linked list will be stored in the same memory address? I don't think I'm rationalizing right. The linked list will be stored like a vector and the data that has a collision will have a pointer to that new node right? I'm sorry if I sound a little bit confusing but that's what I've figured out

@kylebelle246

5 күн бұрын

What if it was always a linked list? even if there are no collisions and the linked list only contains one node. I think that'd make more sense

In cars stuff we have Chrisfix in computer stuff we have my bro right here.

What’s the difference between hashtable and hashmaps?

Thanks man I really appreciate ❤️

@BroCodez

2 жыл бұрын

anytime! Thanks for commenting

@issac17

2 жыл бұрын

Your videos are really helpful...you deserved it❤️

Thanks!

Can you find the values in your hash table from its address?

I'm wondering if these hashcodes been written incorrectly here 3:49 Because the hashcode of String "100" would be 47155, not 48625. and here is why: Initialize hash to 0: hash = 0. Multiply hash by 31 and add the numeric value of the first character '1': hash = (0 * 31) + 49 = 49. Multiply hash by 31 and add the numeric value of the second character '0': hash = (49 * 31) + 48 = 1517. Multiply hash by 31 and add the numeric value of the third character '0': hash = (1517 * 31) + 48 = 47155. so, am I right, these numbers in the example's hashcode are just random numbers and have nothing to do with the righ hashcodes?

@SaiMoen

Жыл бұрын

10:15

I love you Bro

Another day Thank you so much if you ever have membership for no reason ill try to join to money you deserve it

Nice class

Nice👍

What to do when the ids of students are the same? Thanks

how many programing languages you know?

thanks!

so its the exact same as a hashmap?

Thanks Bro

thank god for Bro!

Bro 🤜🤛

thanks bro

Thanks bro 😭

isnt it just jumbling the order? how is that more efficient? I'm confused.

What's the difference between Hash tables and hash maps?

@dispatch-indirect9206

11 ай бұрын

The short answer is you shouldn't use Hashtable and this video shouldn't recommend Hashtable, though this confusion is partly on Oracle. The original collections, especially Hashtable and Vector, were all made to be thread safe. This was only useful in specific cases and the method of making them thread safe was not performant. Per the API docs for Hashtable: _As of the Java 2 platform v1.2, this class was retrofitted to implement the Map interface, making it a member of the Java Collections Framework. Unlike the new collection implementations, Hashtable is synchronized. If a thread-safe implementation is not needed, it is recommended to use HashMap in place of Hashtable. If a thread-safe highly-concurrent implementation is desired, then it is recommended to use ConcurrentHashMap in place of Hashtable._

@migelangelcarrillo1710

11 ай бұрын

@@dispatch-indirect9206 he/she asked for the difference, not your opinion on the subject