This article aims to show how you can create a simple function in Julia to get the factorial of a given number.
What is factorial?
The product of all integers equal to or less in value than the original number — in other words, a factorial is the number of possible combinations with numbers less than or equal to that number.
We symbolise the factorial of a number with “!” (e.g. 4!).
Logical zero factorial proof
As we said, a factorial is the number of possible combinations with numbers less than or equal to that number. Zero has no numbers less than it, but it is a number itself. How many arrangements can I do with 0 items? None at all. This is too a way of arrangement, so 0!=1 (none).
Suppose we have three fruits:
What are the arrangements?
3!=6 as we said previously.
Think similarly for 0!.
Function in Julia
function f(n::Int64) f = 1 if n < 0 print("Factorial does not exist for negative numbers") end if n == 0 print("The factorial of 0 is 1") end if n>0 for i in 1:n f = f*i end println("The factorial is: ",f) end end
Let’s ask the factorial of -3 (n=-3)
Factorial does not exist for negative numbers
Let’s ask the factorial of 0 (n=0)
The factorial of 0 is 1
Let’s ask the factorial of 3 (n=3)
The factorial is: 6
Let’s explain the part of the code below:
for i in 1:n f = f*i end
Firstly, we defined the f as 1.
So, we start with f=1.
for i in 1:3
- f=2*3=6 end
In this article, we gave a simple explanation of the factorial as well we made an easy function in Julia!
Thank you for reading!🤗
Article Cover Photo: Photo by Tommy Bond on Unsplash
Top comments (2)
I liked this article - I wrote a similar one when I was starting out with Julia too!
And then a kind Teacher Assistant for my course came along (with a sneaky smile) and whispered something about some ternary operator...
...Which creeped me out.
But not as much as when I found out about the world of map, reduce, and folds, and all those nifty iterator methods that can get you out of a pinch:
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