Writing a Simple Factorial Program. (Python 2) Khan Academy English Estonian

Writing a Simple Factorial Program. (Python 2)YouTube↗ IA↗(long shot)
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What I want to do in this video is introduce you to a “for" loop.

Selles videos tahan ma teile tutvustada

And we're going to do this by writing a little program

for-tsüklit, me teeme seda kirjutades väikese

that calculates the factorial of a number.

programmi, mis leiab arvu faktoriaali

In case you don't remember what a factorial of a number does,

Ja kui te ei mäleta, mis numbri

if I were to tell you what "1 factorial" [is],

faktoriaal on, kui ma ütleks teile "üks faktoriaalis"

you normally write it as 1 and an exclamation mark ( 1! ) like that.

siis seda kirjutatakse 1!, üks ja hüüumärk.

It literally just means, well, that will just evaluate to 1.

See põhimõtteliselt tähendab, et me hindame ühte

If you say "2 factorial" ( 2! ), that's going to be equal to 2 × 1.

Kui öelda "kaks faktoriaalis", siis see on kaks

If you say "3 factorial" ( 3! ),

korda üks, kolm faktoriaalis on

that's going to be equal to 3 × 2 × 1, and which is going to be equal to 6.

kolm korda kaks korda üks, ehk siis see

And so, if you have any number's factorial,

võrdub kuuega. Mingi arvu faktoriaal on

it's going to be that number

times one number less than that, times one number less than that,

arv miinus üks korda arv miinus kaks...

all the way down to 1.

kuni arvuni üks. Kui see on selge,

So, with that out of the way, let's implement our factorial program.

kirjutame oma faktoriaaliprogrammi, ja

And the way I'm going to do it is, it's going to take an input from the user,

ma teen seda võttes sisendi

It's going to prompt the user

kasutajalt, see ütleb kasutajale, et ta sisestaks numbri,

to put a number that they want to take the factorial of

millest ta faktoriaali leida tahab ning seejärel

and then it's going to calculate the factorial. And so what I'm going to do is,

arvutab faktoriaali. Ja nüüd teen ma seda,

I'm going to use a function that Python provides for us.

et kasutan funktsiooni, mis Pythoniga kaasa tuleb.

And I'm using Python 2 in this video. You'd have to do it slightly different —

Ja ma kasutan siin Python'i versiooni 2, teie peate seda tegema

actually, I'll talk about that in a second —

veidi teisiti, tegelikult ma räägin sellest täpsemalt hiljem, kui te kasutate

if you are using Python 3. Python 2 is what most implementations of Pythoner are built in

Python 3-e. Python 2 on enim levinud versioon

at the time of this video.

selle video tegemise ajal, aga on olemas ka

But there is a Python 3 out there that's kind of a newer version.

Python 3, mis on pisut uuem versioon.

I'll clarify that a bit in a future video. But anyway, we're going to take an input from the user,

Ma räägin sellest täpsemalt tulevas videos, aga igatahes... me võtame kasutajalt sisendi [input()] ning

and we're going to prompt them with a message.

küsime seda teatega, me ütleme:

We're going to say, "Enter a non-negative integer to take the factorial of:". And just so that we get to familiarize ourselves with functions and all.

"Sisesta positiivne täisarv, millest faktoriaal võtta." ja selleks, et me saaks tuttavaks

We're passing an argument to the function.

funktsioonidega, me lihtsalt anname funktsioonile argumendi

And the argument that we are passing to the function —

ning see argument, mida me anname input() funktsioonile

to the input function right over here — is a string.

sellele funktsioonile, on sõne,

And "string" sounds like a very complicated thing,

ja sõne kõlab nagu keeruline asi, aga see on lihtsalt

but it really is just a string of characters. You can view it as a bunch of text.

üks jada tähemärke, mida saab vaadata hunniku tekstina.

it'll present this text to the user,

Ja input() esitab selle teksti kasutajale ning annab

and it'll give them a little input box.

neile sisendikasti. Kui kasutaja sinna midagi

And the user will put something into that input box. It'll evaluate what is in that input box. And then, you could either view it as

sisestab, siis ta hindab seda

having the variable number refer to it,

ning seda võib vaadata nii, et muutuja "number"

or put it in the variable number,

viitab sellele, või võtab endale selle väärtuse (olenevalt

depending on how you want to visualize the variable.

sellest, kuidas te muutujat endale visualiseerite)

If you're using Python 3, you'll want to call "eval" on what's returned from this function.

Kui te kasutate Python 3, te tahate kutsuda eval() funktsiooni tagastatud väärtusele,

This is if you're doing Python 3.

seda siis, kui teil on Python 3.

I'm running Python 2 right now. And if you want to do it exactly the way I'm doing it,

Mul on praegu Python 2. Ja kui te tahate teha seda

I'm using the PyScripter IDE —

täpselt nii nagu mina, siis ma kasutan PyScripter'it

Integrated Development Environment.

IDE - integreeritud arenduskeskkond -- see on tasuta,

It's a free open-source project on a PC.

avatud lähtekoodiga projekt PC jaoks. Aga on olemas ka palju muid mooduseid

But there're many, many ways that you can edit Python. You can really just do it on any text editor — so anyway. So, so far, all we've done is we've taken input from the user

Pythoni kirjutamiseks, seda saab teha ka igas tekstitöötlejas. Igatahes, seni me oleme võtnud

and we're putting it in the variable number.

sisendi kasutajalt ja selle salvestanud muutujasse

What's really cool about Python is

"number", ning Pythonis on lahe see, et me saame

we can just run this program as is and just see what happens.

lihtsalt jooksutada programmi nii nagu ta on ja vaadata, mis juhtub.

So let's do that.

Teeme seda, ma salvestan ta ja

Save it, and I'm going to run it. This little play button runs it in this IDE.

jooksutan seda, see väike Play nupp jooksutab teda IDE-s

And just like we said, it prompts the user:

ning, nagu arvatud, palub kasutajal sisestada

"Enter a non-negative integer to take the factorial of:".

mittenegatiivne täisarv, millest ta faktoriaali leida tahab

So I don't know — let me type in 10. And I [click] OK. Nothing happened.

las ma kirjutan sisse 10 ja vajutab OK, midagi ei juhtunud.

Well of course nothing happened!

Muidugi midagi ei juhtunud, sest ma ei öelnud,

Because I didn't really tell this to do anything. But if we type in "number",

mida selle numbriga tegema peaks. Aga kui me trükime sisse "number" me näeme, et

we'll see that it is now assigned to 10.

talle on nüüd antud väärtus 10, muutuja viitab nüüd

The variable is now referring to the number 10 So now we can use this number and take the factorial of it.

arvule 10 ning me saame seda numbrit kasutada ja leida tema faktoriaal. Ja ma teen seda --

So what I'm going to do — and we're going to do it iteratively —

me teeme seda iteratiivselt, me räägime

we're going to talk more about what that means in the future.

hiljem täpsemalt, mida see tähendab

So I'm going to define another variable called product.

ma defineerin veel ühe muutuja nimega product (tulemus),

I'm start product at 1. What we're going to do is

ma annan talle väärtuseks 1 ja siis me

we're going to start from 1 up to whatever number this is,

alustame ühest kuni misiganes numbrini "number" muutujas on

and keep multiplying the product

Ja korrutame product'i iga kord suurema

by each successively larger number. So we're going to start —

arvuga, alustame nüüd, ma sean siin üles

So I'm going to set up a for loop here —

for tsükli, järgmises videos ma kavatsen

In next video I'm going to really step through exactly what a for loop does.

täpselt läbi jalutada sellest, mida üks for tsükkel teeb.

We're going to — within the for loop —

Aga meie, selle for tsükli sees, me

we're going to define a variable i. This is kind of the classic variable to define in for loops.

defineerime muutuja i, see on selline klassikaline muutuja

And that variable is going to

mida for tsüklites defineerida, ning see muutuja läheb

keep incrementing to larger and larger values

pidevalt suuremaks ja suuremaks, mida edasi me koodis läheme.

as we go through it. So "for i in range" — And for loops in Python are a little bit different than

Ehk siis for in range -- ja for tsüklid Pythonis on veidi

if you were doing it in Javascript or Java.

teistsugused kui näiteks JavaScriptis või Javas

I'll do a future video where we do that.

ja ma seletan seda hilisemas videos, aga range(number)

But "range of number" —

ja selleks, et mõista, mida range mingist arvust teeb,

And just to understand what range of number does is, it provides a list of numbers starting with 0,

see annab listi arvudest alustades nulliga

up to 1 less than that number.

ja läheb kuni arvuni number - 1, seega siin

So over here we already defined what number is,

me juba defineerisime, mis number on. Number on 10,

number is 10. So if I type in range of 10 — or let me do range of number.

seega trükkides sisse range(10) või, las ma teen range(number)

It gives me a list starting with 0 all the way to 9 —

see annab mulle listi alustades nulliga kuni

all the way to 1 less than than 10

arvuni üheksa, st ühe võrra vähem kümnest, see on sama

So that the same thing as range of 10.

asi, mis range(10). Ja see for tsükkel

And what this for loop does is it assigns this i to each term of the sequence —

määrab i väärtuseks iga kord järgmise elemendi listis, see algab

So it starts with [0] — or each term of this list. It starts with [0], and then it'll [do]

ühega ja siis läheb kuni selleni, mis sa talle ütled

whatever you tell it to do in the for loop with i is equal to [0],

for tsüklis, i on võrdne ühega ja siis määrab ta i väärtuseks

then it'll assign i to to be 1. Sorry. It'll start with i equals 0, then it'll go to i equals 1,

ühe, ei, vabandust, see alustab i = 0 ja siis läheb

then i equals 2 then i equals 3 — so on and so forth —

edasi i = 1, siis i = 2, siis i = 3 ja nii edasi ja nii edasi

all the way until you have gone all the way through the list. And so what we can do here is —

seni, kuni ta on listist läbi käinud. Mida me siin for tsüklis teha saame, on defineerida

within the for loop — we can redefine product to be equal to the product (the former product) —

product'i väärtuseks product,

So our new product is going to be our old product times —

s. o. eelmine product, meie uus product on meie eelmine product korrutatud, ja ma korrutan seda

and I'm going to multiply it — times i + 1.

i+1'ga, korda i pluss üks. Ja me sammume siit hoolikalt läbi

We're going to step through it carefully in the next video.

järgmises videos, aga ma tahan, et te juba mõtleksite sellest,

But I want you to think about what it's doing already.

mida see teeb. Ehk siis kui me alustame,

So right when we start, let's say that number ends up being 3.

ütleme, et number on lõpuks 3, siis product

So product gets set to 1. And we say "for i in range".

saab väärtuse 1 ja me ütleme for i in range, ja kui me teeme range(3),

And then, if we do range of 3, then i is first going to be 0.

siis esimene i on 0 ja me võtame oma

And so we're going to take... our old product — so 1 — times i + 1.

vana product'i ehk siis 1 korda i+1, noh, i on 0,

Well i is going to be 0 so 0 + 1 is 1.

seega 0 + 1 on 1, seega see on 1 korda 1

So it is going to be 1 × 1, [which] is going to be 1. Then we're going to assign i to be 1. This is what the for loop does.

see on 1, ja siis me määrame i väärtuseks ühe, see on see, mida for tsükkel teeb,

It iterates. It keeps incrementing.

ta suurendab pidevalt väärtust (noh, ta ei pea alati

Well it doesn't always have to increment. It keeps changing the value of i

suurendama) ja see jätkab i väärtuse muutmist

as it goes through this list.

listist läbi minnes, järgmisel läbimisel

And so the next time around our product is 1. But now i is 1, so 1 + 1 is 2, times 1 is now going to be 2. And then it'll go — it'll set i to be 2.

meie product on 1 aga i on nüüd 1, 1+1 on 2 2 korda 1 on nüüd 2 ja siis see määrab

So it's going to be 2 + 1...

i väärtuseks 2, seega see on 2+1 korda product'i

times what product was from the last iteration which was 2.

väärtus eelmisest tsükli jooksmisest, mis on 2 -- seega see on

And so it's going to be 2 × 3 which is 6

2 korda 3, mis on 6. Ja kui me oleme lõpetanud

And so when we're finally done with this for loop, inside of product —

selle for tsükliga, siis product'i sees, või võiks öelda

or I guess we can say product will be referring to —

product viitab tegelikule faktoriaalile

the actual factorial of the number inputted. So then we can say "print product".

sisestatud arvust, me võime öelda print product

And in Python — in this case right here — the interpreter knows to break out of this for loop

Ja Pythonis teab interpretaator millal for tsüklist välja murda, kui tal saavad otsa arvud,

once it runs out of numbers to assign i to. So, that's why it doesn't run forever.

mida i-le väärtuseks anda. Seetõttu ei jookse ta igavesti.

So, let's see if what we did here actually works.

Proovime nüüd, kas meie kood tegelikult töötab, vaatame,

Let's see if it actually works. So let me — actually — write like this.

kas see tegelikult ka tööle läheb. (Ma kirjutan ta tegelikult nii)

So let's see if this things actually works. So I'll save it. And then let me run it. And so it's asking me,

Vaatame nüüd, kas ta töötab. Ma salvestan selle ja siis jooksutan seda, ja see palub mul sisestada mittenegatiivne

"Enter a non-negative integer to take the factorial of:". So let's try it with 3 — Enter.

täisarv, millest faktoriaal võtta, proovime seda kolmega.

It gave me the right answer. Let's try it again.

See andis mulle õige vastuse, proovime seda uuesti.

So, "Enter a non-negative integer to take the factorial of:".

Sisesta mittenegatiivne täisarv, mille faktoriaali leida.

I don't know, let's try something large: 10.

Ma ei tea, proovime midagi suurt, 10, see töötas!

It worked. [I] assume that you can verify this for yourself.

(Oletades, et sa saad seda ise kinnitada)

So what we have done here is write a very simple program.

Mida me siin tegime, me kirjutasime väga lihtsa programmi, aga

But, it already does something neat —

see juba teeb midagi lahedat, see leiab suvalise

it takes a factorial of an arbitrary number.

arvu faktoriaali. Ja järgmises videos me

In next video, we're going to step through it much more carefully,

läheme koodist palju hoolikamalt läbi, juhul kui

in case this kind of confused you — what this for loop did.

see for tsükkel teile segadust valmistas.

So, just hold with me for the next video, and watch that. That has a little bit of a more careful explanation.

Pidage vastu järgmise videoni ja vaadake siis seda, see seletab veidi hoolikamalt.

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