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### Loops in JavaScript
Here’s a comprehensive guide to loops in JavaScript with examples:
### **1. For Loop**
The for loop is ideal when you know the exact number of iterations you need to perform.
#### **Syntax:**
for (initialization; condition; increment/decrement) { // Code to execute }
#### **Example:**
for (let i = 1; i <= 5; i++) { console.log(`Iteration: ${i}`); }
***Explanation:*
### **2. While Loop**
The while loop is used when the number of iterations is not predetermined and depends on a condition.
#### **Syntax:**
while (condition) { // Code to execute }
#### **Example:**
let count = 0; while (count < 5) { console.log(`Count is: ${count}`); count++; }
***Explanation:*
### **3. Do-While Loop**
The do-while loop ensures that the block of code is executed at least once, even if the condition is false.
#### **Syntax:**
do { // Code to execute } while (condition);
#### **Example:**
let number = 0; do { console.log(`Number is: ${number}`); number++; } while (number < 3);
***Explanation:*
### **4. For-In Loop**
The for-in loop is used to iterate over the properties of an object.
#### **Syntax:**
for (key in object) { // Code to execute }
#### **Example:**
const person = { name: "John", age: 30, city: "New York" }; for (let key in person) { console.log(`${key}: ${person[key]}`); }
***Output:*
name: John age: 30 city: New York
***Explanation:*
### **5. For-Of Loop**
The for-of loop is used to iterate over iterable objects like arrays, strings, maps, or sets.
#### **Syntax:**
for (variable of iterable) { // Code to execute }
#### **Example:**
const fruits = ["Apple", "Banana", "Cherry"]; for (let fruit of fruits) { console.log(fruit); }
***Output:*
Apple Banana Cherry
***Explanation:*
### **6. Breaking Out of Loops**
Use the break statement to exit a loop prematurely.
#### **Example:**
for (let i = 0; i < 10; i++) { if (i === 5) break; console.log(i); }
***Output:*
for (initialization; condition; increment/decrement) { // Code to execute }
### **7. Skipping Iterations**
Use the continue statement to skip the current iteration.
#### **Example:**
for (let i = 1; i <= 5; i++) { console.log(`Iteration: ${i}`); }
***Output:*
while (condition) { // Code to execute }
### **8. Nested Loops**
Loops can be nested inside one another for multidimensional iterations.
let count = 0; while (count < 5) { console.log(`Count is: ${count}`); count++; }
***Output:*
do { // Code to execute } while (condition);
### **9. Infinite Loops**
Be cautious of loops with conditions that never evaluate to false.
#### **Example:**
let number = 0; do { console.log(`Number is: ${number}`); number++; } while (number < 3);
Note: Avoid such loops unless there’s a break mechanism.
### **10. Looping Over Arrays**
Both for and for-of loops are commonly used with arrays.
#### **Example:**
for (key in object) { // Code to execute }
### **11. Looping Over Strings**
The for-of loop is also helpful for iterating through characters of a string.
const person = { name: "John", age: 30, city: "New York" }; for (let key in person) { console.log(`${key}: ${person[key]}`); }
By understanding and applying these loop types effectively, you can handle repetitive tasks and data structures in JavaScript efficiently. Let me know if you need clarification on any specific type!
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