Continuing our exploration of Julia basics, let's take a look at control flow in Julia.

As the name suggests control flow operators help us shape the flow of the program. One typical example might be

To understand these concept, we'll attempt another problem. Nothing better than some hands on experience.

Our challenge is as follows: Given 2 integers (

For example using

Let's begin by printing all the number between

As the name suggests control flow operators help us shape the flow of the program. One typical example might be

`break`

. `break`

tells Julia to exit the loop or do block it's currently in.To understand these concept, we'll attempt another problem. Nothing better than some hands on experience.

Our challenge is as follows: Given 2 integers (

`a`

, `b`

) print the smallest (up to) 5 integers between `a`

and `b`

such that we're not printing numbers divisible by 3.For example using

`a=5`

and `b=23`

we should return:```
5
7
8
10
11
```

If `a`

and `b`

are closer to each other we print everything up to `b`

. Here's another example with `a=2`

`b=4`

```
2
4
```

If you're a complete newcomer to programming, you might want to check out the fizzbuzz post where I explain `mod`

operator etc.Let's begin by printing all the number between

`a`

and `b`

:julia> function fancy_printer(a,b) for i in a:b println(i) end end fancy_printer (generic function with 1 method) julia> fancy_printer(3,7) 3 4 5 6 7

`continue`

in Julia helps us to skip an iteration of the for loop. We'll use this to skip priting numbers divisible by 3.julia> function fancy_printer(a,b) for i in a:b if mod(i,3) == 0 continue end println(i) end end fancy_printer (generic function with 1 method) julia> fancy_printer(3,7) 4 5 7

Alright, one problem down. But what happens if

`b-a > 5`

? julia> fancy_printer(3,12) 4 5 7 8 10 11

That means we have to be careful not with what we print, but how many times we print in total.

To handle this, we'll introduce another variable called

To handle this, we'll introduce another variable called

`printed`

that we can use to count the number of times we printed. If this value reaches 5 we can just end the for loop with `break`

and be done with it.julia> function fancy_printer(a,b) printed = 0 for i in a:b if printed == 5 break end if mod(i, 3) == 0 continue end println(i) printed += 1 end end fancy_printer (generic function with 1 method) julia> fancy_printer(3,12) 4 5 7 8 10

And job done. We print only 5 numbers and none of them are divisible by 3. You might want to check a few more test cases at this point just to make sure our function indeed does what we want it to do.

If you want to make

If you want to make

`fancy_printer`

even fancier you can do so by using some ternary operators in Julia to make your code more compact. The ternary operators `&&`

and `||`

can compress the `if`

blocks into a single line. Here's how our code would look like:julia> function fancy_printer(a,b) printed = 0 for i in a:b printed == 5 && break mod(i, 3) == 0 && continue println(i) printed += 1 end end fancy_printer (generic function with 1 method) julia> fancy_printer(3,12) 4 5 7 8 10

Isn't this pretty? Julia is just pure magic!

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