Java Video Tutorial 9

Code is Here:

Best Java Book :

In this video I go over everything you’d ever want to know about Java Arrays.

I show you how to create arrays, numerous ways to populate them, tricks involving multidimensional arrays, the enhanced for loop, Array library methods and more.


minecraft adventures says:

Why is coulum a string while it’s holding an int and what are those ‘:’ signs used for plz answer.

Teerik says:

2:10 dont you count from 0?

Tomek Zawistowski says:

Bru you explain way to fast. Can’t even keep track of what you are doing. Just take things more slowly for future videos. Good content, but too much to take in when you are going so quickly. !!

Admin Alhabib says:

nice video but, i guess it would be better if u explain each step , I watched the video several times but still there are many things that I couldn’t understand .Thanks!

Jonathyn Major says:

Hey Derek, I love your videos! But I have a quick question on this one, why not do the multiArray like this?:

public class ArrayBuild {
public static void main(String[] args){
int[][] multiArray = new int[10][10];

for(int i = 0; i< multiArray.length; i++) { for(int j = 0; j< multiArray[i].length; j++){ System.out.print("[" + i + " " + j +"] "); } System.out.println(); } } } //My class name is ArrayBuild //I am just curious as to why you converted them to Strings. Thanks in advanced!

Toby Reinhardt says:

A little fast.

Bruno Ribeiro says:

The typed-code with comments combined with the video is a better resource than a semester at a college since we can type as we go at our own pace. This is insanely great at an intermediate level, and I am enjoying every moment of it.
Coding is not for everyone and even though you make insanely easy, people still complaining about it. But I just want to say Thanks Very Much for making these series, and also I am a big fan of your work.

jonasxdufek says:

Nice I made it to part 9! ONLY 84 MORE parts to go xD…..

Nathan Lodge says:

5:22 – multidimensional array

G A says:

Another very good video and covered a good part of arrays.

ronith. NR says:

Hey man really loved your videos, its not boring and at the same time it makes the viewers think about the code. I have one question if we store 1-10 numbers in numbersArray why cant we just use System.out.print(numbersArray)? i tried it but I’m getting a weird output like I@6bc168e5

Evgeni Kuzmov says:

so, the difference btw your row and your column is that row is a basically an X (aka horizontal) and a column is Y (vertical)?

Persus says:

Can someone help me out here?


for (String[] row : multiArray) {
for (String columns : row) {





for (int i = 0; i < multiArray.length; i++) { for (int j = 0; j < multiArray[i].length; j++) { System.out.print(multiArray[i][j]); } }

Horizon says:

Hi , i ‘ve a problem with
int k =1;
while(k < 41 ) {System.out.println('-'); k ++;} System.out.println(); it seem to go in a row but rather a colum,can you help me please.

Joe Vasquez says:

this is the one channel where i automatically give a vid a thumbs up before i even watch it 🙂

dana chiueh says:

what’s the difference between multiArray[i].length and multiArray.length ??

element74 says:

I just realized that in the beginning when you are storing values inside the multidimensional array, you are taking integers and putting them into a String Array. So I guess those integers automatically become a string when that happens, right? I don’t think you mentioned that in the video.

Evgeni Kuzmov says:

15:43. on line 96, you put a “2” into an array, but then an *. like how could that be? I am confused

T S says:

smooth, thx.

Sumit Deshpande says:

can we use enhanced loop to put values in the 2d array….how to do that

Ankita Mishra says:

speaking very fast

Mr. Strange says:

I know this tutorial is old but can someone explain to me why when he printed
an array with random numbers, they were in order instead of random places?

LaMpOcHkA says:

That feeling when learn programming and train listening for IELTS =D

Khelfaoui Abdelbasset says:

thank you so much for this explain..

Brands Programming says:

Question about the method: .length. For example multiArray.length; length is a method and methods always end with ( ). Why isn’t this the case for length. ?

Tarantula guy says:

Video 10 and 8 are the same title just worded differently

Clear Prime says:

I think if you called it “itemInRow” or “stringInRow” instead of column it would be clearer.. Unless that’s all wrong. That’s how I think of it

SOLVED !! says:

in the first (numberarray) array, Why did you make two for loops one for (i)and one for (j) since you are making only one-dimensional array???

Evgeni Kuzmov says:

what is an index fro “|” then? 8:55

Asthetix TV says:

It’s nice and all but geez slow down!

Vj Grimes says:

How did it fix spelling of numToSort to be numsToSort? Looks like an autocorrect found flaw, and how’s that work? 17:06. The field was named numToSort (no s) and he used it three times typing it with an s, numsToSort and at the end, without comment, he fixed the spelling of systme and boom, the spelling of numToSort did find/ and fix, added the s, it fixed itself? Did Eclipse do that?

Shakar .484309 says:

Requirements document
Purchase commitment system
1. The software is to calculate a number of details needed to purchase by a factory in order to make its products.
2. The software must be written In C++ or java programming language on the computer IBM PC.
3. The number of products should be equal to 4.
4. A general aim in the design of the software is to improve portability of software.
5. The system should accept as input (make as text file) the data about a number, amount and price of detail for every types of products.
6. A number of details for every type of products should not be less than 5.
7. The first and second type of products should have 2 same details. The second and fourth type of products should have one same detail. The third type of products should have 2 same details with fourth type and one same detail with first type of products.
8. The operator should be logged in and logged out to the system by login and password.
9. At the beginning an operator must provide the following items of data ( a validation of input data should be provided ):
9.1. Number of every type of products to be produced by the factory for 3 months ahead.
10. The software must produce for each action of an operator a report (the report should be saved in file by the operator’s request). The report must consist of:
10.1. A number of every details needed to purchase.
10.2. The total price for every detail.
10.3. The total price for all details.

Nandini s says:

awesome video watched twice to understand clear 🙂

Rusty Shackleford says:

To anyone getting confused, I would recommend don’t get hung up here. If you don’t understand it, try the best you can to replicate it and at least understand kind of what is gong on, and continue forward. Sometimes things will make sense later or when you understand other concepts. Obviously come back.

Eddie Ibarra says:

Derek, I followed you on twitter. Can you follow back at @ebarrrra ? I need help on a program and don’t have anyone else to turn to. PLEASE

soumen mitra says:

what is the difference between arrays and arraylists???

spookysama says:

yeshh this what ive been looking for a while im a beginner i have been for years lol and this was well explained

Omar Ramzi says:

Slow dowwwnnnnnnnnnnn

Michael Jerry Froimchuk says:

Why would the following not print, but if I change to myarray.length it does run
public class Test{
public static void main(String[] args){
int[] myarray = new int[9];
for (int i = 1; i <= 9; i++){ myarray[i] = i; System.out.println(i); } } }

EzpzHobo says:

the binary search gave me a negative number even tho the number was in the array

Steven Barnes says:

The great thing about video is you can watch it over and over again.

nikhil rao says:

You are going too fast, this way no one can understand arrays so fast specially for first time.

Siddharth Sharma says:

Hey Derek,

I hope you get to read this.
I have a 8 months time until i interview for a really big software company say Google for Software Engineer Entry level Grad.
I’m currently doing my Master’s in CS and will be apply for Graduate opening.

I am going to finish this video series and your Java Algorithms series.

What else do you advise so that i am well over prepared for my Interviews.

You have helped me come a long way from where i was in my Coding and Technical career.
I’ll definitely send you a token of thanks when i land a job. =)


DonCashbro says:

I would say that im a medium java beginner. Studying for the JAVA 7 programmer 1 license since a month or two. And this video/series isnt too slow, or too fast.. this is kinda perfect for me. I did had some errors but found out myself what went wrong, and thats part of being a programmer i guess.. finding bugs and squash em!

Thanks alot m8! Keep them coming.

DAWN says:

it’s not for beginners ! tooo fast !!!

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