Selection Sort Algorithm Explained (Full Code Included) - Python Algorithms Series for Beginners

[@abhivaryakumar3107]

4 years later and you are literally saving my life Such a gift for teaching Thank you

[@lovesignal]

Yeah, you're really talented at teaching. Believe me when I say you've got a real gift. And thank you for sharing it because you don't know how daunting this concept was to me when hearing it from other instructors.

[@janmuhammad7376]

I wish I have teachers like him at my college

[@navodyaliyanage473]

this is absolutely the best series on algorithms, I struggled a lot watching other videos, but this is really amazing, clear and short.

[@utkarshmalik4471]

Hey Derrick this is the best Algorithm Playlist I ever came across So please it's a humble request to make more videos on Algorithm

[@thatcherkane4955]

Sorry to be off topic but does anybody know a way to log back into an Instagram account?? I was stupid forgot the password. I love any assistance you can give me

[@kasontrevor966]

@Thatcher Kane instablaster =)

[@thatcherkane4955]

@Kason Trevor thanks so much for your reply. I found the site through google and Im waiting for the hacking stuff now. Looks like it's gonna take quite some time so I will reply here later when my account password hopefully is recovered.

[@thatcherkane4955]

@Kason Trevor it did the trick and I now got access to my account again. I'm so happy! Thank you so much you saved my account !

[@kasontrevor966]

@Thatcher Kane Glad I could help :)

[@RadioKilledMusic]

def selection_sort(list_a): indexing_length=range(len(list_a)-1) for i in indexing_length: min_value=i for j in range(i+1,len(list_a)): if list_a[j]

[@AlfredDHull]

Still loving this video two years later Derrick!

[@andrewbrower4158]

This tutorial is incredible. Thank you for teaching it so effectively

[@johnhillescobar]

This is a great, amazing and super instructional video. My code for this algorithm is by far more complex. Love the code you created.

[@aqualung1466]

@Maryam Ashraf Below is what I did to test - setup params for "my_range" and "num_elements", or do like I did and make these arguments to your script with sys.argv. import sys import time import random my_range = int(sys.argv[1]) num_elements = int(sys.argv[2]) my_array = [random.randint(1, my_range) for i in range(0, num_elements)] start_time = time.time() bubble_sorted_array = list(bubble_sort(my_array)) bubble_sort_run_time = time.time() - start_time start_time = time.time() selection_sorted_array = list(selection_sort(my_array)) selection_sort_run_time = time.time() - start_time selection_sort_efficiency = bubble_sort_run_time / selection_sort_run_time print("bubble sort took {:.2f} seconds to run".format(bubble_sort_run_time)) print("selection sort took {:.2f} seconds to run".format(selection_sort_run_time)) print("selection sort was {:.2f} times more efficient than bubble sort".format(selection_sort_efficiency)) HTH

[@AlternateMelatonin]

I always wonder, why my professor spends 50 mins lecture just to teach what you show in 5 mins. Thank you always.

[@coolios685]

Dude!!! Derrick this is so awesome. you make these concepts so easy to learn. Keep it up!!!

[@timohelasvuo9650]

Here again for another alogorithm treat! Thanks buddy for yet again great video. Looking forward to look into the code on my comp later today

[@easynow6599]

i have to admit.. I love your short but badass bass music at the intro..

[@shrutikanikhar7987]

You're an amazing teacher.......your videos are very helpful.... Thanks

[@abletmuhtar8979]

Pls teach all of those fundamental algorithms. Thanks

[@rushas]

I like the new intro and the outro! Content is also great!

[@tuborao]

Hi Derrick, first of all I would like to thank you for your videos. They are helping me a lot! I think I found an indentation error inside your script in your githup area. The "if min_value !=1" is not indented with the "for j", and this can cause some sort errors if the first element of the list is equal to the last element. thanks! for j in range(i+1, len(list_a)): if list_a[j] < list_a[min_value]: min_value = j if min_value != i: list_a[min_value], list_a[i] = list_a[i], list_a[min_value] return list_a print(selection_sort([6,7,8,7,6,5,4,5,6,7,6,7,8,9,7,9,0]))

[@cassidybrookland2174]

this fixed my error!

[@lone.wo1f]

Great tutorial! Easy to grasp the concepts.. Subbed!

[@aqualung1466]

Your videos as terrific, thank you. Below is what I came up with - it is almost twice as fast as your code. Why is that?? def selection_sort(unsorted_list): sorted_list = [] while len(unsorted_list) > 0: min_index, min = 0, unsorted_list[0] for i in range(0, (len(unsorted_list) - 1)): if unsorted_list[i] < min: min_index, min = i, unsorted_list[i] sorted_list.append(unsorted_list.pop(min_index)) return sorted_list

[@nowyouknow2249]

Nice video like it's really cool. Fire on bruv!

[@mahadkhurram2950]

Thanks bro, I have an exam tomorrow. And this is really gonna help.

[@DeepakSah3.0]

Love from India - Thanks

[@anirbanc88]

you are the coolest guy ever man, thanks so much

[@SEE.ME.N0.M0RE]

Thank you so much!

[@jiahuizhu3911]

A basic question. How come the 'changing position' could work? such as list[j], list[i] = list[i], list[j]. The first assignment should change list[j], the the second assignment will come back to i, isn't it? Has python put some secrete third item to keep the value temporarily? I am a learner on Python:) Thank you very much in advance

[@rahulnegi456]

its swapping the expression: “ a, b = b, a”, first right gets assigned to first left and second right get assigned to second left at the same time therefore swap values of a and b Search for one liner swapping in python you will get it!

[@carloschaccon8465]

Awesome Derrick, Have you considered a video for Regular Expressions to find data over large files, It is just an idea, thanks again, and keep sharing your knowledge .

[@sebastianlupa7355]

I think calling min_value index_of_min_value could make it clearer, took me a while to figure it out :-)

[@aqualung1466]

Agreed.

[@rayanrahmoune1064]

I did it another way i don't know if it's selection sort def selectionsort(mylist): indexing_length = len(mylist) sorted = [] if indexing_length mylist[value]: min = mylist[value] mylist[0], mylist[value] = mylist[value] , mylist[0] mylist.pop(0) notsorted = mylist sorted.append(min) return sorted + selectionsort(notsorted)

[@alexeyigonen3170]

Thanks for your videos. Will this code be shorter? (prints really help to see the work of the two cycles) for k in range(0,n-1): print('for cycle, k: ', k) for x in range(1, n): print("for cycle, x:",x,a) if a[k] > a[x] and x > k: a[k], a[x] = a[x], a[k]

[@xynerd]

awesome explanation!

[@navodyaliyanage473]

please make more videos on python..on what's after algorithms

[@mehmetozel9001]

Really really easy explained I love u

[@lyricsdelivered]

How do you calculate time complexity

[@erikcarcelen1663]

Hey, amazing video and so beautiful explanation, but I have a question hehe How do you do your animations?

[@Futball860]

Would the result be different if we used indexing_length = range(0, len(list_a))?

[@breakoutgaffe4027]

great explanation

[@jaket750]

thanks man you saved me

[@DispelTV]

When I measure the time it takes to sort with bubble vs selection, selection always takes longer to execute. How is selection better than bubble if bubble takes less time and there's 2 for loops in selection sort which leads to higher complexity O(n^2)? Otherwise, fantastic and simple videos to learn from.

[@krissh6563]

Which software you are using for this video editing

[@abdullahshahid6216]

Line 7: Should the min_value be equal to list_a[ i ]??? Please answer

[@dewman7477]

I don’t get why indexing length only goes to second last item in unsourced list. What if the item in the unworried list is smaller than the previous minimum value?

[@ahmedghanem3126]

Hey Bro You have wrong code if you put [ '1', '4', '19'] output will be [ '1', '19' , '4']

[@gaganjeetsingh673]

No. The code is absolutely fine. You must've implemented it wrong.

[@SReaperz]

his code is the problem to fix it just add if min_value != i: list_a[min_value], list_a[i] = list_a[i], list_a[min_value] min_value = i

[@somyamaniktala1090]

best explanation..

[@sergdonskikh2140]

Hi! Good lessons!

[@hardiktmustudent5851]

hey can you plz tell me a program for to rotate a matrix 90 degree anti-clockwise

[@aminetlemcani693]

Thanks for the video

[@alighaith9717]

thank you for effort Derrick , can you help me with this issue (I have a file of 1000 images and i want to classify it at specific folders i already created for example : from pic 1 to 10 move to folder number 1 and from 12 to 15 to folder number 2 etc ....)I'm biggner on python if you help me I really appreciated it .

[@codex8332]

Please I don't understand the logic behind.the last part. If the min_value != i . Please I need an explanation

[@KeepCoding69]

It's not required actually u can just simply write the switch statement and it would still work.

[@lukasreissig4500]

I am a beginner with Python, which programming evironment is that?

[@shanmuga-raj]

bro can you do more videos like this...

[@betobernal486]

Hi Derrick thanks for your videos. I solved in a recursive way, take a look! def selection_sort(lista,sortedd): if len(lista) !=0: mini=lista[0] for i in lista[1:]: mini=min(mini,i) sortedd.append(mini) lista.remove(mini) selection_sort(lista,sortedd) return sortedd def sorting(lista): return selection_sort(lista,[]) a=[3,3,54,2345,542,456,0,3,4,4,3,6] sorting(a) The problem is that my function requires 2 args, thats why I had to implement the second function. Is there a way to do it this way with only one function? Thanks!

[@johndunn6253]

Good stuff. Thanks

[@luffyhat3852]

your code isnt working for [3,1,2,5,4] this input . it shows the output as [2,1,3,4,5]

[@KeepCoding69]

You need to write the switch statement outside the 2nd for loop. I know it's late but I hope you will find it useful.

[@samuelchen8635]

thank you for making this :0

[@mhd403]

when we changed iMin = j does that change the iMin value or the value stored at list[iMin]?

[@16aasthadoshi95]

imin value whereas list[imin]=j changes value in the list to value of j

[@handle-2]

can someone explain what this line does? its line 14 in his code list_a[min_value],list_a[i]=list_a[i],list_a[min_value]

[@rahulnegi456]

its swapping the expression: “ a, b = b, a”, first right gets assigned to first left and second right get assigned to second left at the same time therefore swap values of a and b Search for one liner swapping in python you will get it!

[@expat2010]

Cool!

[@prasikrar3927]

thanks sir iam from wkwkw island

[@leas9854]

What do i and j stand for?

[@KeepCoding69]

Those are the counter variables

[@MadhushreeSinha]

Isn't the min_val != i : is redundant?

[@rahulnegi456]

yes its not necessary

[@masoud4843]

❤👌

[@darthbolloful]

Derrick stop it you're scaring me

[@rishabhawasthi8192]

David Bowie teaching CS

[@yunkel]

👍

[@AbdullahKhan-dl9lm]

ahhh....The algorithm doesn't work.

[@hamdamjonganijonov8825]

lmao, why is his code sooo easy to understand!

[@rw4877]

You have beautiful eyes man

[@qasimarshad2662]

I have to say you explain well but not for a beginner, I already knew all these concepts and needed a recap and tbh i found your teaching a bit too quick, you need to explain slowly and in more detail

[@strade740]

bro look like rizzler