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Binary Search Algorithm Explained (Full Code Included) - Python Algorithms Series for Beginners

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This video is a part of a full algorithm series. Check them out here:
• Bubble Sort Algorithm ...
#Python #Algorithm #BinarySearch
Binary Search Takes a sorted sequence of elements and figures out if a given element is within that sequence. We'll do this with a series of repeated comparisons. We compare the middle number of our sequence to the item we're searching for. This determines if we continue looking right or left of the midpoint.
The Binary Search Algorithm has a complexity of log2(n) because it doesn't matter how many elements we pass to the algorithm. We'll still cut the entire data set in half each iteration, so the results will happen pretty quickly.
Thanks so much for all the continued support! 5780 subscribers at the time of writing. That's incredible. Thank you all for your continued support of the channel.
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*****************************************************************
Full code from the video:
"Angled brackets not allowed in youtube description."
def binary_search(sequence, item):
begin_index = 0
end_index = len(sequence) - 1
while begin_index #less than= end_index:
midpoint = begin_index + (end_index - begin_index) // 2
midpoint_value = sequence[midpoint]
if midpoint_value == item:
return midpoint
elif item #less than midpoint_value:
end_index = midpoint - 1
else:
begin_index = midpoint + 1
return None
sequence_a = [2,4,5,6,7,8,9,10,12,13,14]
item_a = 3
print(binary_search(sequence_a, item_a))
github.com/Der...
Packages (& Versions) used in this video:
Python 3.7
*****************************************************************
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Опубликовано:

14 авг 2024

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Комментарии : 130

@kiraisonline Год назад

Man I really wish you would bring this series back for other algo techniques, you are my fav python instructor on YT

@osvaldogarcia6154 4 года назад

Thanks a lot for this videos man, they are so simple, but they explain everything in perfect detail

@MyLoweLife 2 года назад

You explained this like I'm 5 years old and thank you bc it makes perfect sense now 😭🙌🏾

@sechvnnull1524 2 года назад

You are amazing! I just started my Data Structures and Algorithms course, and I almost had a heart attack as we covered both linear and binary search algorithms and now have to do math problem for the quiz. Both (0)logn and theta problems. But the most important thing is to understand the logic and what the code is doing. You're doing an awesome job at explaining this!! Thank you.

@salvationprayerfellowship8899 4 года назад

Thanks alot man for the tutorial very well explained you deserve more subs

@jimrakel418 4 года назад

Thank you for your videos. I came across your algorithm series this morning and spent the day watching all 5 videos and learning from your examples. Now I can use them to make my own Python library of tips & tricks to use when I program. Keep up the good work!

@redachikhaoui1209 3 года назад

and also for midpint can be (start + end )//2

@hb5165 Год назад

I'm cramming for my first face-to-face technical interview in 2 weeks and I have to say that I wish I found your channel sooner. Thank you for your effort in making these videos.

@swarooprajpurohit110 Год назад

How did your interview go?

@bedi8049 10 месяцев назад

@@swarooprajpurohit110 bro did not get hired

@in-thegarden 2 года назад

Thanks for the tutorials Derrick they are so easy to understand and well explained. I’m self learning Java and Python for the past three months and your videos are very helpful. Good Teacher.

@toby709 3 года назад

When I studying this using the below list : sequence_a = [1,2,4,5,6,7,8,9,12,14,16,17,22] list_a = 1 it will return 0 as sequence, which looks a bit strange to me...so I add +1 to it, haha print(binary_search(sequence_a, list_a)+1) Btw, it's a good video! Thanks for teaching me!

@pieters286 3 года назад

yes, the list is zero refrenced in code, thus one needs to add 1 again when printing out to natural world.

@ahyungrocks5509 4 месяца назад

Excellent tutorial. Love the algorithm explanation at the end to re-iterate our understanding.

@solomontaiwoabbaly 4 года назад

Thank you very much for this amazing video. I've been searching everywhere for this but there are too complex. But this one is...Schway!!😀

@msms3260 4 года назад

You are sooooo young and smart. I feel so inadequate in regard to thinking capacity 😭. But your videos are amazing, please don’t stop!

@rajkumar.alagappan 4 года назад

Why we should use the formula midpoint= (start+end-start)/2 instead of (start +end)/2 ?

@CodeWithDerrick 4 года назад

I think your solution would work fine too! I haven't tested so don't hold me too it though, haha. In my head I was just adding half of the remaining positions to the current beginning position to get the midpoint is why I wrote it that way

@rajkumar.alagappan 4 года назад

@@CodeWithDerrick ☺️ thank you

@igorverevkin7709 4 года назад

It does work indeed since your begin_index and end_index get new values on every iteration :)

@murtazahonarpoor4252 4 года назад

You are doing a great job man. The videos are short, well explained and very easy to understand. Please keep posting.

@GG-le8bq 2 года назад

Hey Derrick , this is the first time I came across your video and it is so articulate and lucid . I am already subscribing and looking forward to learn more from you .

@elijahlair 2 года назад

Really loved this. Simple and precise. Thanks

@teen_python_go9947 2 года назад

Binary Search Implementation (I tried before seeing your approach): def binary_search(seq, val): print(f"Base Array: {seq}") seq.sort() print(f"Sorted array: {seq}") midpoint = len(seq)//2 while seq[midpoint] != val: if val > seq[midpoint]: midpoint = midpoint + len(seq[midpoint+1:])//2 elif val < seq[midpoint]: midpoint = len(seq[:midpoint]) return f"value is at {midpoint} index in {seq}"

@ilyosbekkarshiboyev7134 2 года назад

Thanks a lot for this videos man

@kockgunner Год назад

For beginners like me, make sure that the while loop has a

@param8378 2 года назад

This solution is better than lead code selection

@UtkarshaB 4 года назад

keep uploading ...Nicely,Thoroughly explained...

@demrieanntinds 3 года назад

hello Derrick, I have a question. What if in the sorted list there is a duplicated number/ numbers? Thanks a lot! :)

@bolawolesegun4248 2 года назад

it will pick the first index of the located value

@blo0buryz__745 3 года назад

I can't figure out how to use binary search and user input. I want to use binary search to look at a list of names the user typed in , ask the user for a name to search and display if the name was there or not. I doubt you'll see this but I thought I would put it out there. Can anyone help me?

@meteerol8082 3 года назад

@Mister Blo0 as he did, user could input the target as an argument in function

@marioandresheviacavieres1923 Год назад

Thanks a lot for the series!! I watch it all

@zisistsatsos2509 4 года назад

I think this code is a little simpler: key=a #the_number_you_are_searching first=0 last=len(L)-1 pos=-1 #the_position_of_the_number while first

@gedtoon6451 16 дней назад

Your algorithm is not quite right. if sequence_a = [2, 4, 5, 6, 9, 9, 9, 10, 12, 13, 14] and item_a = 9 it will return index 5. It is generally accepted that binary search should find the first occurrence, which is 4. Can you correct this problem?

@MrSatz99 3 года назад

Thanks amazing it was! Please upload video on linear search also!

@juliannafotheringham7101 2 года назад

Beautiful videos you angel, so clear and simple.Thank you!!!

@yilu3219 2 года назад

why the midpoint is begin_index + ? why just second part ( end -begin)//2 only?

@hasnainali9295 2 года назад

Absolute clutch, as a comp sci student, you explained better than the teacher (no offence to teacher lol)

@emorgan8698 4 года назад

Hey Derrick. Really enjoy your videos and I think is brilliant the animations you are now adding to the beginning of your videos to explain the theory. I'm trying to create a complexity matrix to determine how complex a project is based on user's input. Was thinking on using radio buttons or something similar for the user to select the input and then generate the result based on the selections. Any ideas on how best to accomplish this (it would need to be a web app)? I am new to Python. Do you think Django would work?

@CodeWithDerrick 4 года назад

Hey Eduardo! Thank you for the kind words! Sorry for the slow reply on this one. Django would definitely be able to handle it for you if you wanted to go down that route. You could collect the input using an HTML form, pass that to your view in django, do your calculations within your view, and then return it back to an HTML page. Django does take a bit of set up in the beginning, but once you get it running, there isn't really a limit to what you can do with it. If you decide to go down that route let me know if you get stuck anywhere - happy to make some tutorial videos around website creation!

@emorgan8698 4 года назад

@@CodeWithDerrick thanks for your reply. if you could do some videos related to this idea that would be great. I'm not a developer so it can get tricky to get this up and running. I have some experience with RPGIV but I now work as Business Analyst. My idea is quite simple. have a table with rows and columns and allow users to select the options using radio buttons and show the risk level at the end. for both the radio buttons and the risk level I'm planning on using Bootstrap. in the meantime I'll keep trying and see how far I can get. keep up the good work and thanks for the help.

@nonserviam24 2 года назад

For anyone wondering. This is a recursive solution. a = [1,2,3,4,5,6] def binarySearch(value, low, high, list): if low value: return binarySearch(value, low, middle-1, list) #here we need to check the upper half as the value is bigger than midpoint elif list[middle] < value: return binarySearch(value,middle+1, high, list) else: return f"Value {value} is not in the list!" print(binarySearch(6, 0, len(a),a))

@wajdy2620 Год назад

im confused by the 7th line. Isnt beginning index always going to equal the same so then it would just cancel out? How could beginning index be 2 different values in the same line?

@user-yp2wr9hl7g 9 месяцев назад

Derrick ,I just completed a python course ,however it is a basic one i am still finding myself rigid while coding how do they I can develop myself to a level where i can write codes smoothly?? Thanks

@JesusAlfredoHernandezOrozco Год назад

Great video and explanation!

@raulsanchez4716 3 года назад

Super clear explanation! Thank you so much.

@udaijitpattnaik4242 3 года назад

what do you actually mean by complexity? is it the time required for the p;rogram to run? if we use quick sort could you please how much time will the program take

@ssengendonazil6985 2 года назад

i do node.js and php but u made it clear for as weel thanx

@6abriel9 4 года назад

Thanks man! excellent explanation, greetings from Argentina

@brainworkout7035 2 года назад

Is it wrong if I find the mid_point like: midpoint = (begin_index + end_index) // 2

@defaltcm 3 года назад

Cannot tell if he is smiling or being held at gun point with those facial expressions lol. At times he seems forced other times he generally seems interested.

@CodeWithDerrick 3 года назад

😂😂

@kda_-uh3vj 4 года назад

2:52 hahaha bruh that glitch in your face, sorry but I can't help but laugh but laugh it off. Btw really good video, it helped me a lot ;)

@rebornproduction2898 3 года назад

While coders where too busy focusing on the code, you was busy focusing on him yeh :)

@lackyyyy3098 3 года назад

@@rebornproduction2898 u should focus on english yeh :)

@vlogiiidawidaaa7408 3 года назад

Is there going to be any more videos on algorithms? Great work!

@shaharyarahmed5777 3 года назад

i noticed a issue if you pass [1, 2, 3, 4, 5] as the sequence the while loop goes infinity

@saiyan5592 5 месяцев назад

Bro pls post more videos on this datas and the algorithms pls ........................ 🙏🙏🙏🙏🙏🙏🙏🙏🙏🙏🙏🙏🙏🙏🙏🙏🙏🙏🙏🙏🙏

@soseofficial3923 2 года назад

very useful brother. thanks a lot.

@zakirhossain7413 3 года назад

gracefully done!

@augusto.carmona 3 года назад

great videos man!

@diegososa5280 3 года назад

Thank you so much. Huge help. Subscribed

@nupurjhankar6745 Год назад

can you do merge sort video

@mustafaa.4690 3 года назад

Who else feels embarrassed? 🤣🤣 Note: Really thank you for this content. It helped me a lot.

@selimtanrverdi9639 3 года назад

Thanks a lot. Very great explanation.

@AreeshaSiddiqui-zy7js 3 года назад

please do a video on data structures and linked list too

@elisasee7538 3 года назад

Hey for line 7 why can't it just be begin+end//2

@methulidulanima5344 2 месяца назад

Thank you !

@kelvin6335 Год назад

Great vid! tysm!

@agesilausii7759 4 года назад

Thanks very good Explanation. Why not put middle = (begin + end)//2 ? Looks simpler. :)

@Change_Test 4 года назад

I stumbled on the answer to this in another video. For certain sizes of input arrays, begin+end can create an integer overflow in some programming languages, so adding the extra steps prevents integer overflow errors. I don't understand what that means, but apparently that's the reason for this format.

@agesilausii7759 4 года назад

paperfish113 really? Thats interesting. I think overflow is when a number is too big for computer memory to handle.

@lucasm4299 2 года назад

@@agesilausii7759 Yes and while (begin + end) may be overflow l, (end-begin) won’t be overflow

@eZaFJDUBB 7 месяцев назад

The program as is returns None every time unless you purposely choose a midpoint equal to the value you're searching for

@priyanshudatta8845 11 месяцев назад

you should cast as jack frost. ♥

@adji97 3 года назад

thanks man this video helps alot

@jpchato 3 года назад

Awesome, Thank you!

@Corrado49 3 года назад

thanks, really help me out!

@madushani6844 2 года назад

Please upload the vedios for Merge sort, shell sort & heap sort as well.🥺❤️

@josepha8415 2 года назад

Great video

@pritam1366 3 года назад

which ide is used in this video

@Sun48100 3 года назад

Thanks, this is helpful.

@LstrnNoob 4 года назад

def search(list,target): for item in list: if list[item]==target: print(i) list=[4,3,6,8,7,9] target=7 search(list,target) 4 #print the index where item belongs

@klejdisbeshi8768 4 года назад

I think it should be if item == target... And this is not binary search so your comment is not valid.

@marclim9304 3 года назад

my number is off by one position what should i do?

@TheGorilla58 4 года назад

It's something I was using by 1981 (When I started with CP/M and PDP11 and VAX sistems). What You are showing it'a the startig procedure of a binary search. What about duplicates? It was already used in 1957 (Peterson, William Wesley (1957). "Addressing for random-access storage". IBM Journal of Research and Development.). Finally, I think U studied well. Pls Read also "Moore School Lectures" from the University of Pennsylvania's Moore School It's an old 1946 Compendium. Here is the link en.wikipedia.org/wiki/Moore_School_Lectures

@loop7210 9 месяцев назад

program code not working properly.IS the code wrong guys ?

@shaharrefaelshoshany9442 3 года назад

wowww, super!!

@thishuman Год назад

Thank you :)

@tonymartin3738 2 года назад

How do you perform 1 through 300

@BiblicalArchaeologyAR 3 года назад

Thank you!!

@davlatbekkobiljonov911 Год назад

thank you

@nikhilparakh3251 3 года назад

Amazing!!!

@armisol00 3 месяца назад

TY BRO

@tareqmahmud3902 3 года назад

Umm, why am I getting TLE's? Time limit expired errors. :)

@temik26 2 года назад

Perfect!

@shiili7699 4 года назад

excuse me, why should "begin" and "end" be assigned to "mid +1" and "mid-1" ? istead of just "mid"

@huzaim.22 4 года назад

Beacause of index in position Hence +1 means after the mid and -1 is before the middle point

@Adam-gp3ij 2 года назад

Awesome

@jingzhuang4168 4 года назад

Thumbs up!

@SEE.ME.N0.M0RE 3 года назад

Thank you so much Derrick, I've been rewatching the playlist almost daily. I have a question: I've tested this on an unsorted list and it did find the index of the element I'm searching for, does this mean that this can work on an unsorted list as well? Many thanks!

@fareselamine8115 2 года назад

Binary assumes you already have a sorted list. If you know the list to start with is unsorted, run it through a sorting algorithm first.

@storm_rising 4 года назад

nrb approves

@spamcocobutt3672 2 года назад

wut if you have an even amount of items

@mariobezuidenhoudt6695 4 года назад

midpoint = (begin_index + end_index)//2

@abdulrameez151 4 года назад

Is the code same for visual code for python on windows

@MegaKash786 4 года назад

Abdul Rameez yes

@avalon4352 3 года назад

ofc. Visual Code is just an IDE. there is no difference in codes

@znpkami 3 года назад

neat!

@saviaggarwal8135 3 года назад

not working in pycharm. Help me!!

@Corrado49 3 года назад

check the indentations

@shahzan525 4 года назад

Make video on merge sort...... Really need it.....

@yunkel 4 года назад

👍

@storm_rising 4 года назад

do you play Minecraft?

@rajivgardas2920 2 года назад

I love you

@Pmills9 3 года назад

I don't get what is the point of this? Why not just return the index of the target number? Wouldn't it be the same either way? This just seems like an overly complicated way to do that. Not bashing you or anything but I just don't see the point of all this extra code

@rinku4240 3 года назад

Hey Derrick Sherrill, your video is amazing. But I would request you to please don't speak so fast during the animation or during the explanation.

@tarzan8110 3 года назад

I've tested all of the sites for free points and only GameCrook works.

@stilgarfifrawi7155 3 года назад

What does it feel like to be born with plastic surgery?

@agsrf6479 4 года назад

If I told you that I am lying to you right now, would I be saying the truth?

@shrutikanikhar7987 4 года назад

yes

@boogiegames8755 Год назад

#tafelpoten die de winkel kottenphark in de schappen heeft Tafelpoten = [30, 50, 70, 80, 85, 90, 100, 120, 150] Tafelpoten.sort() MaatVanKlant = int(input("Welkom bij meubelwinkel khottenphark, wij verkopen hier verschillende maten tafelpoten, wat is de maat tafelpoot die u graag wilt?")) #zorgt ervoor dat er binair gezocht wordt def binair_zoeken(lijst, maat): links = 0 rechts = len(lijst) - 1 while links 0: dichtstbijzijnde_maten.append(Tafelpoten[index-1]) if index < len(Tafelpoten): dichtstbijzijnde_maten.append(Tafelpoten[index]) if len(dichtstbijzijnde_maten) > 1: print(f"helaas is de maat {MaatVanKlant}cm niet beschikbaar. daarentegen zijn de maten {dichtstbijzijnde_maten} wel vergelijkbaar met de maat die u gekozen heeft") elif len(dichtstbijzijnde_maten) == 1: print(f"helaas is de maat {MaatVanKlant}cm niet beschikbaar. daarentegen zijn de maten {dichtstbijzijnde_maten[0]} wel vergelijkbaar met de maat die u gekozen heeft") else: print(f"helaas is de maat {MaatVanKlant}cm niet beschikbaar.")