Julia 101

Lesson 07: Loops in Julia

Loops are a fundamental concept in programming that allow us to execute a block of code repeatedly. In Julia, there are different types of loops, including for loops and while loops. In this post, we will explore how to work with loops in Julia programming language.

For loops

A for loop is used to execute a block of code a fixed number of times. The basic structure of a for loop in Julia is as follows:

for var in collection
    # do something
end

In this code, var is a variable that takes on each value in the collection for each iteration of the loop. Here is an example:

for i in 1:5
    println(i)
end

The loop variable i takes on the values 1, 2, 3, 4, and 5 for each iteration of the loop, and the println(i) statement prints each value to the console.

Julia also provides the break statement, which allows us to exit a loop early.

for i in 1:10
    if i == 5
        break
    end
    println(i)
end

The loop variable i takes on the values 1, 2, 3, and 4, and the break statement is executed when i equals 5. This exits the loop early, and the remaining values are not printed to the console.

While loops

A while loop is used to execute a block of code repeatedly as long as a certain condition is true. The basic structure of a while loop in Julia is as follows:

while condition
    # do something
end

In this code, condition is a Boolean expression that is checked before each iteration of the loop. Here is an example:

i = 1
while i <= 5
    println(i)
    i += 1
end

The loop variable i starts at 1, and the loop continues to execute as long as i is less than or equal to 5. The println(i) statement prints each value of i to the console, and the i += 1 statement increments the value of i by 1 after each iteration of the loop.

Julia also provides the continue statement, which allows us to skip over the remaining statements in a loop and move on to the next iteration.

i = 1
while i <= 5
    if i == 3
        i += 1
        continue
    end
    println(i)
    i += 1
end

The loop variable i starts at 1, and the if i == 3 statement is executed when i equals 3. The continue statement skips over the println(i) statement and the i += 1 statement, and moves on to the next iteration of the loop.

In conclusion, loops are an essential part of programming, and Julia provides several ways to work with them. Whether we need to execute a block of code a fixed number of times or repeatedly as long as a certain condition is true, loops are a powerful tool that we can use to solve a wide range of problems.