Writing a Simple Factorial Program. (Python 2)

Writing a simple factorial program with a "for" loop

[@timmytim9054]

Omg I never knew Sal Khan taught this. The guy literally knows everything ....

[@rouxgreasus]

He's wiser than solomon

[@DHDemid]

Simply the best! My dream is to say you "Thank you " personally !

[@MemoryDealer]

This makes me infinitely happy Sal is posting computer science videos. To those wanting other languages, they'll probably come later. Python is an excellent starting language.

[@murtazaakbarreborn]

This works sir. I was stuck on this. Thank you so much!

[@dellbucket]

legendary, thanks Sal, im a python hacker myself and its good to see you popularizing a great language. I have also gone through alot of your mathematics videos and finance videos and man , i hope KA runs for a very long time !

[@gorkimcgregor8137]

number= int(input("Enter the number= " )) product=1 for i in range(number): product= product*(i+1) print("Factorial of Number is :", product)

[@hedonism13]

That fucking awesome feeling you get when something works. Thanks Sal!

[@brHOLLAND]

Can't wait to see more programming vids. Thanks, Sal!

[@dneelyep]

Very cool! A Computer Science set of videos sounds awesome.

[@andrewvirtual]

thanks you're a life-saver!

[@khanacademy]

@vibol03 Google uses it for a lot of their development (I believe it is their language of choice). Khan Academy's server side code is all Python.

[@attention_shopping]

LOVE programming :) Amazing

[@Swetlana0]

OMG! Am I dreaming? Keep 'em coming!

[@FireheadLazzo]

@ImUncreative100 These are the fundamental skills that every computer programmer MUST know and be familiar with. No, you probably won't use these exact programs in your day-to-day life, but you need to familiar with For Loops and passing arguments in order to build even basic programs. Sal is just laying down the basics of the language. Once you get the basics down, you can begin practicing with larger projects.

[@userr_aa]

Thank u

[@deskasoexe7216]

Great tutorial. Thanks.

[@systemofadown1986]

thanks a lot, it really helps me

[@078matthijs]

awesome, thanks Sal!

[@zkhan2023]

you are truly legend sir

[@mickstarify]

would it be slightly faster if you made it 'for i in range (1, number + 1)' and not add 1 to i in the loop?

[@likewhatijustsaid]

Touché my good sir!

[@Fighterftwful]

Keep it up.. Ill figure this out sooner or later.

[@johnlyons7678]

My problem is get is that I cant seem to convert the string of range to an int. Anyone else get that problem too?

[@woo216]

wow khan on programming now! omg genius much>?

[@Omlet221]

Would adding the eval around input be backwards and forwards compatible with both python 2 and 3? It would just be redundant on 2 right?

[@inbanpythonic415]

you can simple this: import math n = int(input("enter the number: ")) result = math.factorial (n) print(result)

[@pogboy537]

Bruh

[@ananthsb3955]

@@pogboy537 this is what i was looking through.

[@FareehahAdeniran]

Good!

[@itked3]

khan + programming? very cool. plus I've wanted to learn python for quite a while :)

[@mikijasar2594]

Thank you for your video, if I may have a short question. How does your program work in general, given that the input returns a string, and how do you not get an error in the program when you did not convert the input string to an integer?? Thanks in advance for your reply

[@vijaykavuri]

I am able to get the program to display the answer, however I need it to also display the actual calculation, for example if the user enters 4 I need it to display as: 4! = 1 x 2 x 3 x 4 = 24 any help on how to add this in to the code?? Thanks in advance!

[@RaviPrakash-tc5nw]

sir is there any Increment decrement operator in python a++,a--

[@Redexn]

I hate that everyone in the comments is complaining. Are you serious? You should be glad he is teaching programming at all. Maybe in the future he will do a C++ playlist, for now this should be suffice for all of you.

[@ThinkandCreate]

I modified mine a little...to include the index values: def factorial (number): if number

[@Fatima-xb6mp]

"Why isn't the translation feature enabled for some passages, including this one?"

[@pedroalonsoraffoleon7781]

Thanks bro!

[@gryphonkrinsky2405]

my version of python prints all the steps how do I just get it to show the final answer only

[@Grkgermn333]

Really awesome, but you should really do your tutorials in Python 3.xx

[@nooro.o2156]

now it's clear . thanq

[@Hector-bj3ls]

Well yes, but that doesn't help you understand how you would write your own version. While I was learning to program I found it good to practice by writing my own versions of built-in functions. This way I would have something to compare the output to, to make sure my code worked properly.

[@MemoryDealer]

@williamhad If you want to ease your way into programming start with Python. However, if you want to get straight down to business start learning C and C++. Just try both and after a while you'll decide.

[@henik9]

If I ever have a chance of learning how to program, it'll be from Sal.

[@AlderDragon]

I did it the opposite way. I just made my for-loop start at 1. for i in range(1, number+1): product = product * i

[@annabelhuang4529]

thanks a lot, but this program doesn't work on Pycharm. What is the correct program on Pycharm?

[@williamhad]

@xXSparky117Xx whats better for a beginner c++ or python?

[@Callalily_]

thank you

[@jumung2012]

whoa, so is this how calculators work?

[@makiolo2011]

how can I make the program ask me constantly. for example; I put a 5, so i tells me 240, and then gives me the option to put a new number without closing the program. I know I have to use a while, but I don't know how :S

[@vibol03]

@ashconnor yeah i know thx for pointing that out

[@noxure]

omg, Sal is teaching computer science. I would be really pissed off if it turns out you're better than me at this too... but then I have something good to watch, so it's all good. :p

[@vibol03]

@woo216 yes absolutely

[@777jimi777]

Sal please do a C++ playlist :D

[@ethanabaker1]

When I do this, no window shows up for input...the program just runs until I kill it...why? I'm using CodeRunner on OS X 10.6.8.

[@SaniSensei]

it works, but I wouldn't say it's easier. You are passing the "number" variable to the range() function and at the same time change "number" inside the loop. It works and it's okay, if you know that python passes the "number" variable to a local variable inside of range(), but for someone less experienced it might be hard to make out, what's actually going to happen, since changing the variables, that are used inside of the loop header, is generally a nasty thing. So no: not recommended.

[@prithvib8662]

How would you modify this so that it would only do even numbers? E.g. 6! would equal 48 instead of 720 since 6*4*2 = 48?

[@manasansiva8878]

number=int(input('Type your number: ')) product=1 for i in range (0,number+1,2): # 2 means stteping by 2. if i==0: continue else:product=product*i print(product)

[@hedonism13]

Whenever I try to open PyScripter, I get an error box saying: "Python could not be properly initialized. We must quit." Wut do?

[@hedonism13]

When will this be on the KA site?

[@hz2229]

Thank you Sir! O7

[@sokhengchork6450]

How about C++?

[@wesselbindt]

Nice, always wanted to learn python. The white background really throws me off, though.

[@S3b1Videos]

I'm viewer number 55.555 :-)

[@777jimi777]

@hedonism13 You are probably running x64 windows. You have to download the x86 python from Python's website.

[@Anubispop2]

SALMON? He's not a fish, dude.

[@saligari666]

we want to learn C,or C++ and some object focused programming

[@hedonism13]

Sadly, once this computer science playlist (which I've seen people drooling for on his channel since he revealed his CS background) is finished, I'm pretty sure that's just about everything he can teach us. Then we'll probably start getting new lecturers, unless Sal wants to go back to University to learn engineering or philosophy.

[@superdau]

@riyadhelalami If you mastered one programming language, it's easy to start another (at least most of them). The concepts are the same. So just follow these videos and there'll be no need for a Java or C-Tutorial.

[@RiyadhElalami]

Please do java or C++

[@nullentrophy]

here mine : i=0 fenter=input("eded:") for i in range(1,fenter+1): for a in range(2,fenter): i=i*a print i

[@woo216]

@vibol03 dude they are all similar well at least thats what i have relised if you learn one you can easily learn the others

[@zuberuber]

number = input() for i in range(1,number): [tab]number = number * i print number isn't it easier?

[@ForgedEggs]

@riyadhelalami Get a book on the language you want.

[@ali-emam-al-badi4790]

There will be a little correction .. number=input('enter a number:') fact=1 for i in range(int(number)): fact=fact*(i+1) print(fact)

[@xbl4ck7]

I just need to Enter a numerator for an improper fraction: Enter a denominator Write improper fraction as a mixed number How do i do that? i know its probably simple....

[@sansamman4619]

I think you have learned how to do it by now, but still: #from and import are two python concepts you should study prperly from fractions import Fraction #we will be using fractions so you want to import fractions # ( basically to change decimals to fractions ...etc ) def dec_to_proper_frac(dec): #we use this as our main way of converting a fraction to a decimal sign = "-" if dec < 0 else "" #we use this so we no longer need to deal with negative numbers frac = Fraction(abs(dec)) #abs (absolute value) #and this part deals with the actual conversion #pretty simple stuff, you can see what's happening just by looking at it return (f"{sign}{frac.numerator // frac.denominator} " f"{frac.numerator % frac.denominator}/{frac.denominator}") #this is the main way of doing it so you can find it easily online as well

[@redMotif]

You also have to download and install python

[@vibol03]

@khanacademy ahh i need to do more research before i comment next time!

[@t3po7re54]

Is this the first video of the series?

[@rockingamingwiththesahit2145]

No

[@jfmjaco5941]

Aren't all inputs in python, strings

[@hedonism13]

@bka320 Thanks, 7 days later...

[@8bitmagic]

DOES IT MATTER, the point is to learn a programing language :/ it makes others easier to learn

[@KaushikMishrakk]

You can even do this! number = int(raw_input('Enter the value:')) product = 1 for i in range (1,number+1): product = product * i print product

[@jiango]

explain please, the code works but I don't understand. If user inputs 5 so the range is 1 to 6, why isn't the outcome 1x1x2x3x4x5x6 resulting in 6! (720) ?

[@sanjeetpal5343]

import math num = int(input("Enter the number:")) result = math.factorial(num) print("The factorial of the given number is", result)

[@Schindlabua]

I guess its fine in this example, but please DO NOT use eval() with actual code that you are releasing somewhere.

[@xeztan]

I'm lost :(

[@Farzaneh58]

+xeztan see the next video about for loop

[@ashconnor]

@vibol03 Quite an ignorant statement.

[@silverreyes7912]

what does this guy not know how to do. lol. what did he get his degree in? Is he an engineer by trade?

[@nelsonwetmore]

OOOOR a function :D def factorial(x): '''Returns the factorial of x (x!)''' ans = 1 for i in range(1,x+1): ans = ans*i return ans # factorial(5)

[@jiango]

explain please, the code works but I don't understand. If user inputs 5 so the range is 1 to 6, why isn't the outcome 1x1x2x3x4x5x6 resulting in 6! (720) ?

[@nelsonwetmore]

On "pythoncentral.io/pythons-range-function-explained/" " range([start], stop[, step]) start: Starting number of the sequence. stop: Generate numbers up to, but not including this number. " So for 5!, I want range to be 1 to 6 because it won't include 6. Just Pythons Syntax is all I can say.

[@jiango]

nelson wetmore thanks for replying, good explanation

[@nelsonwetmore]

You are welcome :D

[@rouxgreasus]

Andrei = "Human" if Andrei == WokenUp: wake Up else: continue sleeping if Andrei == Hungry Eat else: continue doing current thing

[@hz2229]

Bruh

[@rouxgreasus]

@@hz2229 why?

[@hz2229]

@@rouxgreasus actually is kinda makes sense, but you def cannot write that in the programme lol

[@rouxgreasus]

@@hz2229 let's fix it... Andrei = "Human" if Andrei == "WokenUp": print("wake Up") else: print("continue sleeping") if Andrei == "Hungry" print("Eat") else: print("continue doing current thing") there we go!

[@hz2229]

@@rouxgreasus yes much better lol

[@rustemhuseynli5898]

error

[@abhishekkaran1205]

This is wrong range value not in str

[@eyebeebak]

this is why python sucks and why php is better.