Basic constructions

Do you want to do programming? Engee uses the programming language Julia! If you are not familiar with Julia, start with First steps. Introduction to technical calculations Engee and the course "Welcome to Engee". And examples provides different scenarios for usage of Julia. This will be useful for beginners and experienced programmers alike!

Basic constructs such as loops and conditions allow you to control the flow of program execution. They are essential for implementing complex logic and data processing. In this article, we will look at the basic constructs of the Julia language to help you get started in Engee.

Loops

Loops are constructs that allow you to repeat the execution of a particular block of code multiple times. There are two basic types of loops used in Julia: for and while. They help automate repetitive tasks, such as processing data, performing calculations, or searching collection items.

The `for` loop

The for loop is used to iterate over the elements of a collection (such as an array, range, or string). It is ideal when the number of iterations is known in advance.

Example: iterating over the elements of an array and displaying them on the screen.

for i in [1, 4, 0]
  println(i)
end

Output

1
4
0

In this example, the variable i takes values from the array [1, 4, 0] and for each value, a block of code inside the loop is executed.

The for loop can also be used to work with ranges:

for i in 1:5
  println("Iteration: ", i)
end

Output

Iteration: 1
Iteration: 2
Iteration: 3
Iteration: 4
Iteration: 5

Here the loop is executed 5 times, looping through the values from 1 to 5.

Loop `while`

The while loop executes a block of code as long as a certain condition is fulfilled. It is useful when the number of iterations is unknown in advance and depends on the fulfilment of the condition.

Example: incrementing the i variable until its value is less than 5.

i = 1
while i < 5
  println("Current value: ", i)
  global i += 1
end

Output

Current value: 1
Current value: 2
Current value: 3
Current value: 4

In this example, the loop is executed as long as the variable i is less than 5. At each iteration, the value of i is incremented by 1.

When to use `for` and `while`

Use the for loop if the number of iterations is known in advance or if you want to loop through the elements of a collection.
Use the while loop if the number of iterations depends on the fulfilment of a condition that may change during the execution of the program.

Both loops can be useful in different situations, and the choice between them depends on the task at hand.

If you want to interrupt the loop before it completes, use the break keyword. To move to the next iteration without executing the remaining code in the current iteration, use continue.

Example with break:

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

Output

Example with continue:

for i in 1:5
  if i == 3
    continue
  end
  println(i)
end

Output

Terms and conditions

Conditional statements allow you to execute code depending on the fulfilment of certain conditions. Julia uses the if-elseif-else construct:

x = 4
y = 10
if x < y
  println("x is less than y")
elseif x > y
  println("x is greater than y")
else
  println("x is equal to y")
end

Output

x is less than y

Basic constructions

Loops

The for loop

Loop while

When to use for and while

Terms and conditions

Useful links

The `for` loop

Loop `while`

When to use `for` and `while`