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Object Iteration with for...in Loop | Advanced Object Manipulation
JavaScript Data Structures
course content

Course Content

JavaScript Data Structures

JavaScript Data Structures

1. Introduction and Prerequisites
2. Objects Fundamentals
3. Advanced Object Manipulation
4. Mastering Arrays
5. Advanced Array Operations

bookObject Iteration with for...in Loop

In this section, we will explore advanced concepts of working with objects. Specifically, we will cover iteration through objects and helpful methods JavaScript offers to work with objects effectively. Let's get started.

for...in loop

To work with the properties of an object, including iterating through them, we can use the for...in loop. This loop allows us to traverse an object and access its properties and their values.

The for...in loop is a construct in JavaScript designed specifically for iterating over the properties of an object. It provides a way to access each property's name (key) and its corresponding value.

Here's the basic syntax of the for...in loop:

  • key: A variable that will hold the name of the current property during each iteration;
  • object: The object we want to iterate through.

Iterating Through Object Properties in Practice

Let's consider an example with an object representing a flower:

Now, let's use the for...in loop to iterate through the properties of the flower object and log each property name and its value:

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const flower = { genus: "Allium", species: "Allium sativum", color: "Purple", height: 24, isEdible: true, isBlooming: true, }; for (let key in flower) { console.log(`Property: ${key}, Value: ${flower[key]}`); }
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1. What is the primary purpose of the `for...in` loop when working with objects?
2. What does the `key` variable represent in the `for...in` loop?
3. Which part of the `for...in` loop syntax contains the object you want to iterate through?
4. What will be logged when iterating through the `motorbike` object's properties in the code below?
What is the primary purpose of the `for...in` loop when working with objects?

What is the primary purpose of the for...in loop when working with objects?

Select the correct answer

What does the `key` variable represent in the `for...in` loop?

What does the key variable represent in the for...in loop?

Select the correct answer

Which part of the `for...in` loop syntax contains the object you want to iterate through?

Which part of the for...in loop syntax contains the object you want to iterate through?

Select the correct answer

What will be logged when iterating through the `motorbike` object's properties in the code below?

What will be logged when iterating through the motorbike object's properties in the code below?

Select the correct answer

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Section 3. Chapter 1
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