Iteration Lesson No.2

Intro to iterations

The Break Statement

• We use it to terminate a loop/switch

%%js

for (let i = 0; i < 10; i++) {
  if (i == 6) {
    break;
  }
  console.log(i);
}

<IPython.core.display.Javascript object>

Output

0

1

2

3

4

5

• When i = 6, the break statement is run, and it ends the loop early

Continue Statement

• used to restart a while or for loop
• when used, ends the current iteration, and continues the next iteration

%%js
for (let i = 0; i < 10; i++) {
    if (i == 6) {
      continue;
    }
    console.log(i);
  }

<IPython.core.display.Javascript object>

Output

0

1

2

3

4

5

7

8

9

• Notice how it skips 6 and continues the loop

For each loops

• We did this in the previous lesson to loop through an array

%%js
const colors = ['red','blue','yellow','green','black'];

for (let i = 0; i < colors.length; i++){
    console.log(colors[i]); 
}

<IPython.core.display.Javascript object>

There is a different way to do this

%%js
const colors = ['red','blue','yellow','green','black'];

//color = i
for (let color of colors) { //checks each element in the list
    console.log(color); //prints each color
}

<IPython.core.display.Javascript object>

• These blocks of code both have the same output

Output

red

blue

yellow

green

black

Edit Popcorn hack 3 to work with for each loops

Nested For Loops

• You can put for loops inside for loops
• these are called nested for loops
• pretty simple

Example

%%js

for (let i = 0; i < 3; i++){
    for (let j = 0; j < 3; j++){
        console.log(j); 
    }
    console.log('\n');
}

<IPython.core.display.Javascript object>