Essential JavaScript

For Loop

Another type of loop is a for loop. For loops make it easy to act on a specific range of values.

For loops are similar to while loops, but they have two extra statements between the parentheses.

Look at this example of a while loop turned into a for loop:

let i = 0;
while (i < 10) {
for (let i = 0; i < 10; i++) {

Notice how the for loop is much cleaner? We can see all the code that deals with counting on a single line.

The three statements inside the parentheses run at specific times:

  • The first statement runs before anything else in the for loop. It is often used to initialize variables for the loop.
  • The second statement is identical to the while loop condition. The loop will run as long as this condition remains true.
  • The third statement runs at the end of each loop. It is usually used for moving to the next item.

Use Cases

For loops are a great choice for working with strings, as they allow us to easily work through each index of the string:

let myString = 'The New York Times';
for (let i = 0; i < myString.length; i++) {

Learning Goals

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