loops.md

Loops in JvaScript

Loops in any programming language are used to run a piece of code repeatedly. Using loops, you can run the same code with different values repeatedly without writing the instructions again and again.

Types of loops in JvaScript: ✧ for loop ✧ while loop ✧ do while loop ✧ for...of loop ✧ for...in loop

for loop

For loop, it works best when you know how many iterations will be required in advance.

There are three parts of for-loop:

1. initialization to declare or initialize a variable.
2. condition to determine whether the loop will keep executing; if the condition is false, the loop will be terminated.
3. increment and decrement refer to the change in the value of a variable.

When a condition is true, the code inside the loop will execute.

Syntax:

for (initialization; condition; increment/decrement) {
// Code to be executed in each iteration
}

Example: Here's an example of for loop to print even numbers from 0 to 20

for (let i = 2; i <= 20; i += 2) {
console.log(i);
}

while loop

In a `while loop``, you execute a block of code repeatedly as long as a certain condition is true.

The `while loop`` works well when the number of iterations is unknown.

It starts by checking whether the condition is true; if it is, the while loop's code block is then executed, and the process is repeated until the condition is true.

Example:

let i = 0;
while (i < 5) {
// Code to be executed in each iteration
i++;
}

for-loop vs. while-loop

One key difference between for-loop and while-loop is that while-loop is used when you do not know how many iterations are required.

On the other hand, for-loop works best when you know how many iterations will be required in advance.

do while loop

If you want to run the code block at least once before checking the condition, use `do-while`` loop.

After the first iteration, if the condition is true, the loop continues to iterate until the condition is false, at which point it terminates.

Example:

let i = 0;
do {
// Code to be executed in each iteration
i++;
} while (i < 5);

for...of loop

The for...of loop is used to repeatedly iterate over and perform some action on each value of an iterable object, such as an array, a string, or a NodeList.

Syntax:

for (variable of iterable) {	
// block of code to be executed
}

Example: Hera's an example how you can use it.

If you were a chef, you might have a variety of ingredients for a special recipe. You must make a list of every ingredient you will need to purchase and include it in your shopping list.

const ingredients = ["flour", "eggs", "milk", "sugar"];
console.log("Shopping List:");
for (const ingredient of ingredients) {
console.log(`- ${ingredient}`);
}

for...in loop

The for...in loop is used to iterate through all of an object's enumerable property keys.

Syntax:

for ( variable in object ){
// block of code to be executed
}

Example: Hera's an example how you can use it. If you are a developer working on a project, you might have an object that lists different tasks and their current states.

const tasks = {
"task1": "completed",
"task2": "in progress",
"task3": "not started",
};
for (const taskName in tasks) {
const status = tasks[taskName];
console.log(`Task ${taskName} is ${status}.`);
}

Key points:

• for...of is for objects and it returns values
• for...in is for iterables and it returns object indices

That's pretty much it for today. I really hope you find this helpful.

Needs some improvements? Feel free to contribute to this repository.