HashMap Java Tutorial #50

[@alexlorenlee]

If you’re new to programming but want a career in tech, I HIGHLY RECOMMEND applying to one of Springboard’s online coding bootcamps (use code ALEXLEE for $1,000 off): bit.ly/3HX970h

[@latedeveloper7836]

Exemplary tutorial, as always. Timings + my notes below that might help others: 1:45 An example of how hashmaps can help 2:05 Creating and naming a hashmap 2:40 How to add values to a hashmap using the .put method 3:52 Why you should use a generic and data type for type safety when creating a hashmap + how to add this 4:25 Why you need 'Integer' [i.e. class type] for a hashmap (can't take primitive 'int' type) 5:00 Test print of hashmap (default output displays in set notation) 5:30 Calling a specific value from the hashmap - .get call 5:50 Start of more advanced hashmap functions - user + password example 6:15 Creating a hashmap with specific type for type safety 6:33 How to add users and passwords - .put method 7:32 How to remove elements from a hash map - .remove method 8:08 Check if hashmap contains a specific value - .containsValue 8:42 Difference between Values and Keys in a hashmap using .containsValue and .containsKey method calls 9:23 How to replace a value (password) - .replace method 10:10 Key difference between hashmaps and array lists - hashmaps don't have a specific order whereas array lists have an index 11:00 Simple summary of what a hashmap is

[@InkMask]

:D

[@zorienx]

Thank you for this!

[@burakgul2136]

This video is awesome. Your english is clear and understandable. I like it 👍

[@7own878]

Here, after concentrating to get what was said in the Indian accent, one time too often.

[@bobbobertson9063]

@@7own878 it gets tiring to heat the same accent from computer science tutorials all the time

[@rxtechandtrading]

I know...we can actually understand this man, unlike all the other idiots who make tutorials

[@josephsanchez2061]

I don't know if you'll see this since it's an older video but you're probably the only programming tutorial KZbinr that's relatable. The rest of them are super smart and do know what they're talking about (so are you obviously) but for some reason, you admitting that a certain topic or part of a topic confuses you helps me understand the material more when you explain it.

[@unitedtomato5444]

He understands what not knowing something was like. I really appreciate that!

[@ulanalibek7225]

Yes the name itself used to make me think that this HashMap thing is one of the most complicated things in Java. Your tutorial made it look like a piece of cake. :) Thanks! keep up the good work.

[@waterflowzz]

It’s not complicated to use but the implementation of a hash map is a bit more complex than just a 2d array. Hashmaps use a hash function to store the key value pair so that it doesn’t have to go through the whole hashmap using a for loop, Big O(n), when looking for a key. The hash function lookup makes it so that it is Big O(1). In other words the hash function makes it so that the lookup of a key is faster.

[@enochphetteplace8729]

This is actually the best description of HashMaps I have seen yet

[@luka-j-ovanovic]

For anyone with a python background, hashmaps are the same as dictionaries.

[@murkkz1679]

Thank you bigman

[@MANOJKUMAR-mb2uw]

Yes

[@nathaniepeter5707]

Thank you

[@mir.9805]

Ah the more you know.

[@brandonstrobel1365]

Saved me 11 minutes !

[@gnovakov]

Love your tutorials, so clear and concise! you just get to the point and it just makes sense!

[@fakejake8723]

Seriously you taught a semestre worth of studies under 20 min. I thank you. I couldn't figure this out until your video. Please make more videos on data structures. I get your explanations.

[@abdullahmamun1823]

just as simple as u.thanks.it is a one kind of social work.we need people like u.

[@bieberfever161098]

I finally understood, thanks for the video!! Btw the sound of your keyboard is so satisfying😨

[@danishuddin9752]

The UI you created it beautiful!

[@shirinall9080]

This young dude is my favorite tutor in youtube !!

[@lukedavis6711]

Its called HashMap because it's a data structure that uses the hash function to generate a mapping of keys and their corresponding values.

[@skat4]

Been studying for my Software Engineering Interview, and these videos are so helpful!

[@h0tar]

That keyboard is amazing! Thanks for clearing up hashmaps for me, makes it easier when we get there at school.

[@yogeshpandey9549]

the most simplified yet extremely informative tut on hashmap. great work m8 :)

[@abhi.marc90]

Wow thank you I was unable to understand hash maps until I stumbled upon your video. Thank you :)

[@biggie2123]

I finally understand HashMaps. Thank you so much!

[@kzfingerprint]

Your videos are amazing! Thank you!!! You break down complex things so that I can better understand what's actually going on

[@MaximumJoy]

This is so helpful. Your explanations and presentation are perfect.

[@biscuitbutb4106]

These tutorials are awesome. You make java look so easy. Thanks for these easy tutorials!!

[@mageshsankaran6521]

you explained it effortless

[@basithtafadher8743]

Teaching method really awesome. Wish your good health.

[@supriyagupta922]

lovely dialogue delivering, excellent quality of video, concepts told in lay man terms. enjoyed and learnt. keep up the good work Alex. :)

[@johncsanchez9763]

great tutorial. I understand it alot than my teacher. Thanyou! post more java tutorial

[@johnvishwas9117]

You're the best coding tutor!

[@miledsahar2840]

i don't usually write comments but your tutorials are so good and helpful. keep going !

[@psalkin]

Best hashmap tutorial ever!

[@mflr121]

Excellent video, I understood everything. Thank you!

[@lukedavis6711]

In the statement 'int a = 10'; 'a' is not a String but a non-static field.

[@victorwolff]

What type of keyboard is that? The sound is so satisfying XD

[@skyeleake9943]

looks like a HHKB TypeS (torpre silent 45g switches)

[@geromemanicia3809]

This was most helpful. I also want one of your keyboards but for now I'm gonna stay with my measly CTRL from drop.

[@PratyushMishra7]

instead of typing system.out.println() use sout followed by ctrl+space or cmd+space

[@sandianexpress1198]

or just do sysout followed by ctrl + space.

[@usertyfoon]

That was great! Many thanks, bro!

[@fabianmaisch2423]

Very nice man! Helped me a lot👍🏼

[@cacmang42]

you're a great teacher, keep going 💪

[@ljka]

Just like any other concepts, we learn basic of Java and integrate those knowledges to better understand more complex concepts. HashMap is named as it is because it possesses properties of Map and uses hashing logic in organizing and structuring data. Data Structure ✌🏼 Cool vid

[@ahmediqbal9869]

for anyone that is wondering, it is called a HashMap because it uses a technique called hashing.

[@groupcoop409]

Best hashmapping tutorial! super easy to understand well delivered! more tutorials to come THANKS! :D

[@testtester5693]

Thanks dude! Really good !!

[@adultishgambino8713]

Such a good tutorial, straightforward and useful

[@thischannelisnomore1283]

Most useful on teaching me hashmaps, Thank you so much!

[@jong.4864]

This helped me a lot, thank you Alex!

[@helalali9799]

i am an indian and i actually dont watch englishmen video because i couldnt get the pace of english, but you are the 1st youtuber whose video i watch very confidently. my request is that can you start a series to make people competetive coder from 0 to hero.

[@jakubsowikowski9654]

Awesome video!

[@andreloureiro4447]

Simply and great, thanks

[@Big-Timbo]

So I'm not entirely sure, as I'm learning CS myself. However, I believe it's called Hashmap, because it seems the main use is for usernames and passwords. a typical way that passwords are stored securely is to create hash values (essentially an encrypted version of that same password) and have those stored in a database instead of the plain text. It would make sense to me that it's called hash map as you're creating a link between what could be used for user's hashed passwords linked to the user account.

[@NilEoe]

My personal (unverified) theory is that hasmaps are called that way because the hash symbol # could represent the idea of 2 dimensions (grid) opposed to an array which would be a single line

[@ayoubrayanemesbah8845]

hash is an arbic word تهشير which mean make a marke on something

[@aliciaabella7307]

Great Great Great tutorial !!

[@shantanushende6]

Amazing Video!!!!!!! keep going!!! can't wait to learn more.

[@bafers1]

Really like your videos, thanks for putting them up! Quick question though.... why do you not use your Mac keyboard :) ?

[@andywei5518]

very friendly for beginner :)

[@aydinvahdat7816]

I swear to god this is the last one I’m gonna watch today

[@michaelsd28]

best teacher ever

[@carlosblanco1574]

Really good video

[@yerffej370]

Bro why does KZbin keep recommending this. Fine! I’m here. I clicked it

[@Greenmarty]

2:00 It's called HashMap because it uses hash key to access values in the background and implements Map interface and extends AbstractMap class. If you would write your custom HashMap it would be array of linked lists. Length of the array would not be equal to number of stored key-value pairs. Instead array stores linked list heads, where each list node has hash key, value and points to next node. Hash key is hash version of the key you inserted. To access the value nodes are iterated until hash key matches.

[@nobel978]

Thank you so much, you're an awesome teacher.

[@marta9385]

What keyboard are you using? I like the mechanical keyboard but I don't know what one I should buy. Thank you for your video it´s really useful!

[@JoshuaPack]

So, in PHP, is a hashmap just an Associative Array?

[@sk8terkyd326]

this functions almost the same as dictionaries in python right?

[@miriamarelymartinezcampos238]

I loved the names haha "happy" and "fun", thank you so much for your explanation you made easier to understand

[@sunmit_productions]

Thank you very much Alex! I was struggling with HashMap for all day, and your video really helped!!

[@lesliecastelan7814]

thank u for ur service to my grade

[@RicardoPires2023]

Hello Alex and thank you very much for your videos. They are awesome! For this video in particular, it was not clear to me what are the differences of HashMap and ArrayList, and how too choose which to use. Thank you again!

[@Oleks_krulikovskyi]

Thank you ❤

[@Falzer]

So for Python, its dictionary for javascript, its Object literal for java its hashmap?

[@ovey2214]

Thank you for explaining things so well. You make otherwise complicated things sound so easy to understand. Bless you brother!

[@glorysonhorace3265]

Very educative

[@preetamackermann3038]

You make everything so simple. Thanks a lot !

[@ElColombre27360]

Nice video, but I don't agree with the explanation approach. I think that the best approach is using the math concept of function: that's exactly what a map is.

[@DeepakSingh-vh7yx]

every topic to him is pretty confusing

[@SuhasGowda4695]

Thank you for the video. This covers almost everything for novice learners.

[@afifkhaja]

Terrific!

[@Universestyle]

With my software setup, I have to name the public class something else then "HashMap", then it works.

[@uttamsingh5465]

Love from Nazia Farheen ❤❤❤❤❤❤❤❤❤❤❤❤❤❤❤❤❤

[@ItsAnu276]

U are just aswwm Lee ty mate👍

[@Brlitzkreig]

So glad to see how your channel has grown over time. You really deserve it!

[@simonescarantinotorregross9182]

hashmap is basically a library of method, right?

[@321jeR]

Hye Alex, im love your tutorial

[@haziq903]

Can you do tutorial doing HashMap without importing

[@nyxielia]

Thank you so much!! Finally a good explanation! Can you please make more videos on Data Structures :-)

[@itsofficial5381]

Which softwares are you using to design and edit your videos ? Please please tell me....i like you design tooooooooooooo much.. please tell me ?😥😥😥

[@khushiozha9370]

what more can we learn if we have already done python,js,sql and html currently am doing java.... what are more languages we can learn plzzz guide me sir ... I am interested in programming currently am in 10th standard

[@VIGNESHWARANSita]

can u give a content for entry set in map

[@darthpepe6761]

I was working on a master order assignment where we had to make a map of cookie variety and its numBoxes sold. This video was very helpful since he basically said, here is the assignment. You're gonna need to know Maps. I appreciate the tutorials. Thank you so much.

[@iwatchedthevideo7115]

Quality stuff! Will sub for more!

[@khyrzzxujhynnefanega9073]

Your videos are helpful,,but my brain is a bit slow so uhmmmm---- thank you so much I learned something today.

[@goddnny3320]

Good video :) Is it possible to make a hashmap with 3 or morge strings?

[@alexlorenlee]

Hacker-Report yea totally you can add as many as you want

[@c7iogamer264]

thank you for making coding tutorials that arent mind numbing

[@ishowLow]

macbook gay :(

[@saucer79]

fax😩

[@aiandesilva6416]

The amount of times this guy has saved my GPA is crazy

[@haythembargaoui4813]

thank you

[@Seebzters]

So, why is it unsafe to replace a key in a HashMap?

[@jesthenoob6514]

Cant we use Arrays to compile the things?

[@Calupp]

Mmm that keyboard thoncc af

[@mdhossain529]

You are great my son. May God Bless you.I am 48 but steel I am your student. Thank you very much.

[@patrickaero1767]

Are HashMaps the same thing as HashTables? Do you think it is possible to do quadratic and linear probing using HashMaps?