This course is aimed at students and practitioners of Data Sciences for building Predictive Analytics models for research and commercial purposes. 
 
Machine Learning can be used to solve prediction problems for classification and regression. In this course, we discuss about using Machine Learning for building Regression Models. We will use Python Language. 
 
In Python, we have many options for building Machine Learning solutions like Tensor Flow, Keras, etc. In this project, we use Scikit-Learn. 
 
Scikit-Learn provides a comprehensive array of tools for building regression models (Scikit-Learn also has tools for solving classification problems). The concepts learnt in this project can be extended to build Neural Networks and other types of models using tools like Tensor Flow or Keras, etc using Python or any other language like R. 
 
Before diving into building Regression Models using Scikit-Learn, the course discusses the concepts required to understand the process and mechanism for building such models. As it is easy to understand the concepts working them through Excel, and also it can be experienced visually, we start the course through explanation of the associated concepts using Excel. 
 
This course requires the Learners to have prior knowledge of Computer Software programming, knowledge of programming using Python and also some knowledge of Predictive Analytics.

English

Introduction

One of the simplest form of Regression is Linear Regression. We start our discussion with Linear Regression so that we can appreciate what exactly we are trying to do for predictive analytics using Regression.
Also, try to notice the characteristics that evolve from Linear Regression which can be used in general for evaluating the goodness of a Regression.

Understanding Linear Regression

In this video, we will try to understand Linear Regression in one variable and Linear Regression in multiple variables using Excel.
We discuss Linear Regression in one variable as it is possible to represent this data on a 2-dimensional graph. The regression equation for this problem will be a straight line and will have a simple equation in the form y=mx+c. I have attached the Excel File used in the video along with so that you could check these visualisations.
Further, using Excel, we can extrapolate this regression idea to other forms of regression like Logarithmic regression or Exponential regression or Polynomial regression. All these forms of regression are readily available in Excel.

Understanding Linear Regression through Excel

We know that we can create a number of Regression Models for the same data set. So, how do we know which of the Regression is the best for the given data.
Further, every Regression model needs some criteria for optimising itself. What are these criteria what the Regression Models use?
We discuss these criteria for finding the goodness of the Regression Models in this video.

How to measure goodness of a Regression Model?

The features or the independent variables will have their own range of values. Now, some values will be large and some will be small. For example, if we have housing data, the number of bedrooms will be possibly 1-digit numbers and the square feet of the house will be in hundreds or thousands.
The variables which have higher range of values will influence the Regression Equation more. So, it is required to scale all the variable to similar range so that each variable has more or less similar influence on the Regression Equation.
In this video, we will discuss scaling methods of Min-Max Scaling and Normalisation.

Scaling Variables

Random Forest Algorithm was developed for solving Classification problems. However, this was found to be good for solving Regression problems as well. In actual scenario, Random Forest Algorithm gives much better predictions as compared to many other Regression Models for most kinds of data.

Understanding Random Forest Algorithm for Regression

Support Vector Machine (SVM) Algorithm was developed for solving Classification problems. However, this was found to be good for solving Regression problems as well. SVM Algorithm are very good to making good predictions for models where large outliers exist and also when there are missing values in the data set.

Understanding Support Vector Machine (SVM) for Regression

In this video, we will discuss the minimum number of libraries and functions we require for creating the Regression Models using Scikit-Learn.

Libraries & Functions in Scikit-Learn required for creatingRegression Models

In this video, we run through a complete process of building regression models using Scikit-Learn.

Building Regression Models using Scikit-Learn

In this video, we discuss the next steps after this course.

Next Steps

Building ML Regression Models using Scikit-Learn

Director - Professional Services

Tier 18

<h2>In this course:</h2>
<ul>
 <li>you will learn bedroom interior design ideas</li>
 <li>you will find out how to decorate your bedroom&nbsp;</li>
 <li>you will learn special interior design for single and double bedroom house</li>
 <li>you will learn interior design tips and get practical advice 
</li>
</ul>
<h2>Get started with interior design by learning the principles of decor and learn how to choose a perfect home style. Explore all useful tips and essential artistic techniques to create a great room decor! Follow these practical hacks in the examples to become a cool interior designer.</h2>
<h2>Looking for bedroom ideas to maximize your space? In this course, you will learn how to take your small bedroom to the next level with design, decor, and beautiful patterns. 
 
Are you ready to enjoy this interior design course? The tutorial will help you to achieve all your professional goals in designing. &nbsp;</h2>

Basic interior design tips for bedroom

Interior Designer 

Free Tier

Interior Design

Design

<h2>How does the course work? 
 
Interior drawing</h2>
<ul>
 <li>you will learn how to how to draw buildings and perfect geometric objects</li>
 <li>you will get practical tips you need to know about two-point perspective drawing</li>
 <li>you will learn how do artists create one or more vanishing points in their artwork</li>
</ul>
<h2>Useful perspective drawing hacks</h2>
<ul>
 <li>you will learn how to draw a stylish room</li>
 <li>you will learn perspective drawing tips and hacks</li>
 <li>you will learn how to draw a cityscape in 2 point perspective</li>
</ul>
<h2>This online course will answer your questions about interior design and help you improve your skills. Learning 2-point perspective is one of the most useful things you can do as a designer. After the course, you’ll be able to draw rooms accurately.</h2>

How to draw a room in 2-point perspective for beginners: interior design

Error

Tier 1

Hope everyone had a great summer. I’ve never before used this space to pay tribute to a particular songwriter or executive, but sometimes this business is so focused on tomorrow’s hits that we pay only momentary attention to the passing of people who quite literally created the industry of which we’re apart. The lyrics of Jerry Leiber, equaled only by Chuck Berry, established the mythical, iconic imagery of rock ‘n’ roll– they captured teen spirit long before Kurt Cobain, with humor and energy and an attitude of rebellion that runs through all of the popular music from the Fifties onward. Nick Ashford, along with his wife and collaborator Valerie Simpson, brought the passion and power, and also the innovative chord progressions, of gospel music to Motown, and carried it all the way through the modern r&b era, from Ray Charles (“Let's Get Stoned”) to Marvin Gaye and Tammi Terrell (“Ain’t Nothing Like the Real Thing”) to Diana Ross to Chaka Khan to Mary J. Blige. Ashford & Simpson’s music is a common thread that runs from soul to disco to R&B to house music to hip-hop and ties it all together as one type of music - the kind that inspires you lifts you up and makes you move.

Beyond momentary introductions at industry events, I have never had the opportunity to know personally either Jerry Leiber or Nick Ashford. That’s actually okay. The beauty of music is that I didn’t really need to. Some of the first songs I have ever learned to play on guitar were the classic Leiber & Stoller Elvis hits like “Hound Dog” and “Jailhouse Rock”. In college, one of my first arrangements to be performed was of Ashford & Simpson’s “You’re All I Need (To Get By)”. One of my biggest hits as a songwriter, Martha Wash’s “Carry  On”, was very much inspired by “Ain’t No Mountain High Enough”. I danced at Sound Factory to Danny D’s remix of “I’m Every Woman” (the greatest dance song ever) when Junior Vasquez played it for twenty minutes at 6 in the morning. Nick Ashford and Jerry Leiber felt like friends to me - as they do to millions of other people around the world.

Interestingly, both men were innovators not only in their music but also in the music business. Leiber and Stoller were some of the first songwriters to become producers and publishers as well. They were the original modern writing/production team, and also co-publishers of their work, a rarity in those days. In fact, they essentially pioneered the “production deal” with a label, working as freelancers, rather than employees of the company. Ashford & Simpson were writers and producers as well, but broke new ground by then parlaying their success behind the scenes into long careers as performing artists, with hits like “Solid” and “Found a Cure”. Where most songwriters seem to start as artists and then move into writing songs for others, Ashford and Simpson flipped the script and went the other way, not unlike what writers/artists like Sean Garrett and others have done today.

It’s always risky to try to divine lessons from careers like Jerry Leiber or Nick Ashford - the creative genius of songwriters at that level is not particularly transferable. If you’re as talented as those two, you can do a lot of things that might not work for other people. Nevertheless, there are a couple of obvious truths that are common to both men, even though they came from different backgrounds and eras, and had very different musical gifts. It’s worth noting:

1. There’s strength in numbers. And two is a very good number.

Granted, everyone has their own way of working. But you can’t argue with certain patterns, and one of those is that songwriting just seems to work better in two-person teams. Leiber & Stoller followed Rodgers & Hart, Rodgers & Hammerstein, George & Ira Gershwin, Fields and McHugh, Waller & Razaf and the list goes on. Leiber and Stoller were followed by Lennon & McCartney, Jagger & Richards, Bacharach & David, Elton John & Bernie Taupin, and of course, Ashford and Simpson. Certainly, there are dozens of legendary songwriters who worked entirely on their own. And while I’m not a big fan of today’s “song by committee” writing method, with five or six writers all chipping in bits and pieces, I can’t deny that it has yielded some successful records. But in the end,  the songwriting duo seems to be the most consistent hit-producing machine ever devised. If you’re working solo and not getting to where you want to be, either professionally or creatively, it might mean that you need to find your other half.

2. The best American popular songs are almost inevitably rooted in black music forms.

If there’s one enduring formula in American popular music, it’s this: trends and forms originate in the culture of black America, and then are developed, refined, sometimes diluted and often homogenized into mainstream pop music. Jazz became show tunes and popular standards; funk became disco; hip-hop became urban pop. Thanks largely to Leiber & Stoller, the blues became rock ‘n’ roll, leading not only to Elvis, but to The Coasters, the Drifters, Ben E. King, and ultimately everyone from the Beatles and Stones to Zeppelin. At the same time, the music of the black church was transformed into soul music, and Ashford and Simpson turned it into Motown, into disco, into pop. It doesn’t matter what race the creators come from - they’re all drawing water from the same well. Even today, we see forms like dub-step reshaping pop music once again. The musical tradition that is an integral part of black culture is a seemingly unending source of inspiration and innovation.

3. Songwriting is not merely an expression. It’s communication.

At a meeting not too long ago, a songwriter matter-of-factly informed me that she wrote music primarily for herself - to express her feelings and ideas. It’s something I seem to hear increasingly often, usually as an explanation of why the song has no chorus, why the lyric makes no sense, why the song appears to fit no known sector of the market. To Jerry Leiber or Nick Ashford, I’m sure the idea of music solely as a means of personal expression would have been inconceivable. That’s not to say that there wasn’t plenty of Jerry Leiber or Nick Ashford’s personality in their music. It’s rather to say that they aimed to communicate their point of view to the listener. They weren’t aiming at something personal and introspective, but rather something celebratory, engaging, and compelling. “Ain’t No Mountain High Enough” or “Stand By Me” are about connecting with the audience. That’s why they’re hits for generation after generation. This is the legacy of Jerry Leiber and Nick Ashford. They built a business around entertainment in the best sense of the word, finding a raw emotional connection, an interaction, shared, visceral energy between writer, performer, and audience. Too often now, it’s become a business of cool detachment, of artistic statements, “vibe”, and marketing concepts. Listening instead of dancing. The distant wave of a hand, rather than human touch. Every songwriter reaches inward to some degree or another. But the greatest songwriters also reach out.

Hope everyone had a great summer. I’ve never before used this space to pay tribute to a particular songwriter or executive, but sometimes this business is so focused on tomorrow’s hits that we pay only momentary attention to the passing of people who quite literally created the industry of which we’re apart. The lyrics of Jerry Leiber, equaled only by Chuck Berry, established the mythical, iconic imagery of rock ‘n’ roll– they captured teen spirit long before Kurt Cobain, with humor and energy and an attitude of rebellion that runs through all of the popular music from the Fifties onward. Nick Ashford, along with his wife and collaborator Valerie Simpson, brought the passion and power, and also the innovative chord progressions, of gospel music to Motown, and carried it all the way through the modern r&amp;b era, from Ray Charles (“Let's Get Stoned”) to Marvin Gaye and Tammi Terrell (“Ain’t Nothing Like the Real Thing”) to Diana Ross to Chaka Khan to Mary J. Blige. Ashford &amp; Simpson’s music is a common thread that runs from soul to disco to R&amp;B to house music to hip-hop and ties it all together as one type of music - the kind that inspires you lifts you up and makes you move.
 
Beyond momentary introductions at industry events, I have never had the opportunity to know personally either Jerry Leiber or Nick Ashford. That’s actually okay. The beauty of music is that I didn’t really need to. Some of the first songs I have ever learned to play on guitar were the classic Leiber &amp; Stoller Elvis hits like “Hound Dog” and “Jailhouse Rock”.&nbsp;In college, one of my first arrangements to be performed was of Ashford &amp; Simpson’s “You’re All I Need (To Get By)”. One of my biggest hits as a songwriter, Martha Wash’s “Carry&nbsp; On”, was very much inspired by “Ain’t No Mountain High Enough”.&nbsp;I danced at Sound Factory to Danny D’s remix of “I’m Every Woman” (the greatest dance song ever) when Junior Vasquez played it for twenty minutes at 6 in the morning. Nick Ashford and Jerry Leiber felt like friends to me - as they do to millions of other people around the world.
 
Interestingly, both men were innovators not only in their music but also in the music business. Leiber and Stoller were some of the first songwriters to become producers and publishers as well. They were the original modern writing/production team, and also co-publishers of their work, a rarity in those days. In fact, they essentially pioneered the “production deal” with a label, working as freelancers, rather than employees of the company.&nbsp;Ashford &amp; Simpson were writers and producers as well, but broke new ground by then parlaying their success behind the scenes into long careers as performing artists, with hits like “Solid” and “Found a Cure”. Where most songwriters seem to start as artists and then move into writing songs for others, Ashford and Simpson flipped the script and went the other way, not unlike what writers/artists like Sean Garrett and others have done today.
 
It’s always risky to try to divine lessons from careers like Jerry Leiber or Nick Ashford - the creative genius of songwriters at that level is not particularly transferable. If you’re as talented as those two, you can do a lot of things that might not work for other people. Nevertheless, there are a couple of obvious truths that are common to both men, even though they came from different backgrounds and eras, and had very different musical gifts. It’s worth noting:
 
1.&nbsp;There’s strength in numbers. And two is a very good number.
 
Granted, everyone has their own way of working. But you can’t argue with certain patterns, and one of those is that songwriting just seems to work better in two-person teams. Leiber &amp; Stoller followed Rodgers &amp; Hart, Rodgers &amp; Hammerstein, George &amp; Ira Gershwin, Fields and McHugh, Waller &amp; Razaf and the list goes on. Leiber and Stoller were followed by Lennon &amp; McCartney, Jagger &amp; Richards, Bacharach &amp; David, Elton John &amp; Bernie Taupin, and of course, Ashford and Simpson.&nbsp;Certainly, there are dozens of legendary songwriters who worked entirely on their own. And while I’m not a big fan of today’s “song by committee” writing method, with five or six writers all chipping in bits and pieces, I can’t deny that it has yielded some successful records. But in the end,&nbsp; the songwriting duo seems to be the most consistent hit-producing machine ever devised. If you’re working solo and not getting to where you want to be, either professionally or creatively, it might mean that you need to find your other half.
 
2.&nbsp;The best American popular songs are almost inevitably rooted in black music forms.
 
If there’s one enduring formula in American popular music, it’s this: trends and forms originate in the culture of black America, and then are developed, refined, sometimes diluted and often homogenized into mainstream pop music. Jazz became show tunes and popular standards; funk became disco; hip-hop became urban pop. Thanks largely to Leiber &amp; Stoller, the blues became rock ‘n’ roll, leading not only to Elvis, but to The Coasters, the Drifters, Ben E. King, and ultimately everyone from the Beatles and Stones to Zeppelin. At the same time, the music of the black church was transformed into soul music, and Ashford and Simpson turned it into Motown, into disco, into pop.&nbsp;It doesn’t matter what race the creators come from - they’re all drawing water from the same well. Even today, we see forms like dub-step reshaping pop music once again. The musical tradition that is an integral part of black culture is a seemingly unending source of inspiration and innovation.
 
3.&nbsp;Songwriting is not merely an expression. It’s communication.
 
At a meeting not too long ago, a songwriter matter-of-factly informed me that she wrote music primarily for herself - to express her feelings and ideas.&nbsp;It’s something I seem to hear increasingly often, usually as an explanation of why the song has no chorus, why the lyric makes no sense, why the song appears to fit no known sector of the market. To Jerry Leiber or Nick Ashford, I’m sure the idea of music solely as a means of personal expression would have been inconceivable. That’s not to say that there wasn’t plenty of Jerry Leiber or Nick Ashford’s personality in their music. It’s rather to say that they aimed to&nbsp;communicate&nbsp;their point of view to the listener. They weren’t aiming at something personal and introspective, but rather something celebratory, engaging, and compelling. “Ain’t No Mountain High Enough” or “Stand By Me” are about connecting with the audience. That’s why they’re hits for generation after generation. This is the legacy of Jerry Leiber and Nick Ashford. They built a business around entertainment in the best sense of the word, finding a raw emotional connection, an interaction, shared, visceral energy between writer, performer, and audience. Too often now, it’s become a business of cool detachment, of artistic statements, “vibe”, and marketing concepts. Listening instead of dancing. The distant wave of a hand, rather than human touch. Every songwriter reaches inward to some degree or another. But the greatest songwriters also reach out.

Musician

Songwriting is not merely an expression. It’s communication. The musical tradition is a seemingly unending source of inspiration and innovation.

Reach out and touch: music inspiration

Let’s face it — Javascript is a funny language, to say the least. And the internet is filled with articles articulating this. But it’s simple, powerful, and ubiquitous, and learning a trick or two wouldn’t go amiss. In this article, we’ll be discussing a tricky bit in Javascript — copying.

Consider two variables a and b. You have a value stored in a, which you wish to copy into b. This can be done as follows

Now you might be wondering what was the point of showing that, for that was obvious. Bear with me. This method holds true so long as a and b are of primitive data types — string, number, boolean, etc. The above bit of code will copy the value stored in a to b and then, changes in one won’t affect the other. Again, obvious.

Let’s take this one step ahead now. What if a was say, an array? “Yea, what about it?”, I hear you ask. Logic dictates that this should not make any difference. The array in a can be copied into b in exactly the same way and changes toa won’t affect b and vice versa.

console.log(a); // Result: [1, 2, 3, 4, 5]

console.log(b); // Result: [1, 2, 3, 4, 5] 

console.log(b); // Result: [1, 2, 3, 4, 5, 6]

console.log(a); // Result: [1, 2, 3, 4, 5, 6]

Surprised? I’m sure that at least a couple of you reading this would certainly be. Feel free to try it out and see it for yourself.

This behavior is a result of the way Javascript works. In JS, Arrays, Objects, and Functions(let’s collectively call them Objects, because that’s how JS sees all 3 of them), are treated differently from String, Number, Boolean, Null, and Undefined(the Primitives). While the Primitives are passed by value, Objects are passed by reference.

This essentially means that when we assign a Primitive variable to another Primitive variable, like in our simple copy case, the value stored in one variable is copied into the other and after this copying, they are independent of each other. On the other hand, in the case of Objects, when you assign an Object variable to another Object variable, both variables are essentially referring to the same Object in memory — just as how Christiano Ronaldo and CR7 refer to the same individual.

It’s because of this pass by reference nature of objects that we saw the arrays from the above code snippet behave the way did. When we work on a or b, we are effectively working on the same array, referred to by using different names.

It’s also worth noting that JS is not exclusive in this behavior — Typescript, which is essentially a superset of JS, shows the same behavior. So does Python.

Time and again, situations might arise when you need to copy an Object-type variable and not end up altering the source variable while working on the copy and vice versa.

Introduced in ECMAScript 6(ES6), the spread operator(…) solves this very problem. Using the spread syntax, you can extract the value of an Object, which can subsequently be copied into another variable.

As can be seen from the above code snippet, once we use the spread syntax to copy Objects, changes in one variable don’t affect the value stored in the other, and vice versa. What has essentially happened here is that by extracting and copying the value of a to b, we ensured that both a and b are not referring to the same object in memory.

As much as spread operator is a lifesaver as far as copying Objects go, there is a catch and a big one at that. Consider the following piece of code.

console.log(a); // { name: 'John Smith', marks: [100, 98, 95, 99] };

console.log(b); // { name: 'John Smith', marks: [100, 98, 95, 99] }; 

console.log(a); // { name: 'John Smith', marks: [100, 98, 95, 99, 100] };

console.log(b); // { name: 'John Smith', marks: [100, 98, 95, 99, 100] };

Looks like we still have problems after all.

As you can see, despite using the spread operator to copy the value of a to b, changes to johnMarks affected the marks field for both a and b. This happens because the copying done by means of the spread operator is what is known as a ‘shallow copy’.

Shallow Copy is one where while copying an Object, we copy values of the main Object but pass the reference of Objects within it to the copy. Thus, in our case, both a and b store a reference to the same johnMarks Object. What we need in such cases, is a ‘deep copy’.

In a deep copy, values of the Object, as well as those of Objects within it are copied out, meaning that if we deep copy a to b, the marks field will hold the value of johnMarks and not a reference to it.

While various ways exist to perform a deep copy in Javascript, including creating a custom function that could maybe recursively do a shallow copy to emulate a deep copy, I usually go with a simple yet effective method. All we need are two methods already available to us out of the box.

const b = JSON.parse(JSON.stringify(a)); 

Let’s face it — Javascript is a funny language, to say the least. And the internet is filled with articles articulating this. But it’s simple, powerful, and ubiquitous, and learning a trick or two wouldn’t go amiss. In this article, we’ll be discussing a tricky bit in Javascript — copying.
 
Consider two variables a and b. You have a value stored in a, which you wish to copy into b. This can be done as follows
 
<code>const a = 'Hello';</code>
<code>const b = a;</code>
 
Now you might be wondering what was the point of showing that, for that was obvious. Bear with me. This method holds true so long as a and b are of primitive data types — string, number, boolean, etc. The above bit of code will copy the value stored in a to b and then, changes in one won’t affect the other. Again, obvious.
 
<code>const a = 10;</code>
<code>const b = a;</code>
<code>b += 10;</code>
 
Let’s take this one step ahead now. What if a was say, an array? “Yea, what about it?”, I hear you ask. Logic dictates that this should not make any difference. The array in a can be copied into b in exactly the same way and changes toa won’t affect b and vice versa.
 
<code>const a = [1, 2, 3, 4];</code>
<code>const b = a;&nbsp;</code>
 
<code>console.log(b); // Result: [1, 2, 3, 4]&nbsp;</code>
 
<code>a.push(5);</code>
<code>console.log(a); // Result: [1, 2, 3, 4, 5]</code>
<code>console.log(b); // Result: [1, 2, 3, 4, 5]&nbsp;</code>
 
<code>b.push(6);</code>
<code>console.log(b); // Result: [1, 2, 3, 4, 5, 6]</code>
<code>console.log(a); // Result: [1, 2, 3, 4, 5, 6]</code>
 
Surprised? I’m sure that at least a couple of you reading this would certainly be. Feel free to try it out and see it for yourself.
 
<h1>So, what happened there?</h1>
This behavior is a result of the way Javascript works. In JS, Arrays, Objects, and Functions(let’s collectively call them Objects, because that’s how JS sees all 3 of them), are treated differently from String, Number, Boolean, Null, and Undefined(the Primitives). While the Primitives are passed by value, Objects are passed by reference.
 
This essentially means that when we assign a Primitive variable to another Primitive variable, like in our simple copy case, the value stored in one variable is copied into the other and after this copying, they are independent of each other. On the other hand, in the case of Objects, when you assign an Object variable to another Object variable, both variables are essentially referring to the same Object in memory — just as how Christiano Ronaldo and CR7 refer to the same individual.
 
It’s because of this pass by reference nature of objects that we saw the arrays from the above code snippet behave the way did. When we work on a or b, we are effectively working on the same array, referred to by using different names.
 
It’s also worth noting that JS is not exclusive in this behavior — Typescript, which is essentially a superset of JS, shows the same behavior. So does Python.
 
<h1>What’s the solution?</h1>
Time and again, situations might arise when you need to copy an Object-type variable and not end up altering the source variable while working on the copy and vice versa.
 
<h1>Enter Spread …</h1>
Introduced in ECMAScript 6(ES6), the spread operator(…) solves this very problem. Using the spread syntax, you can extract the value of an Object, which can subsequently be copied into another variable.
 
<code>const a = [1, 2, 3, 4];</code>
<code>const b = [...a];&nbsp;</code>
 
<code>console.log(b); // Result: [1, 2, 3, 4]&nbsp;</code>
 
<code>a.push(5);</code>
<code>console.log(a); // Result: [1, 2, 3, 4, 5]</code>
<code>console.log(b); // Result: [1, 2, 3, 4]&nbsp;</code>
 
<code>b.pop();</code>
<code>console.log(b); // Result: [1, 2, 3]</code>
<code>console.log(a); // Result: [1, 2, 3, 4, 5]</code>
 
As can be seen from the above code snippet, once we use the spread syntax to copy Objects, changes in one variable don’t affect the value stored in the other, and vice versa. What has essentially happened here is that by extracting and copying the value of a to b, we ensured that both a and b are not referring to the same object in memory.
 
<h1>Yay! We’re sorted — not so fast</h1>
As much as spread operator is a lifesaver as far as copying Objects go, there is a catch and a big one at that. Consider the following piece of code.
 
<code>const johnMarks = [100, 98, 95, 99];</code>
<code>const a = {&nbsp;</code>
<code>&nbsp;&nbsp;name: 'John Smith',&nbsp;</code>
<code>&nbsp;&nbsp;marks: johnMarks</code>
<code>};</code>
<code>const b = {...a};&nbsp;</code>
 
<code>console.log(a); // { name: 'John Smith', marks: [100, 98, 95, 99] };</code>
<code>console.log(b); // { name: 'John Smith', marks: [100, 98, 95, 99] };&nbsp;</code>
 
<code>johnMarks.push(100);&nbsp;</code>
 
<code>console.log(a); // { name: 'John Smith', marks: [100, 98, 95, 99, 100] };</code>
<code>console.log(b); // { name: 'John Smith', marks: [100, 98, 95, 99, 100] };</code>
 
Looks like we still have problems after all.
 
As you can see, despite using the spread operator to copy the value of a to b, changes to johnMarks affected the marks field for both a and b. This happens because the copying done by means of the spread operator is what is known as a ‘shallow copy’.
 
Shallow Copy is one where while copying an Object, we copy values of the main Object but pass the reference of Objects within it to the copy. Thus, in our case, both a and b store a reference to the same johnMarks Object. What we need in such cases, is a ‘deep copy’.
 
In a deep copy, values of the Object, as well as those of Objects within it are copied out, meaning that if we deep copy a to b, the marks field will hold the value of johnMarks and not a reference to it.
<h1> </h1>
<h1>How to perform a deep copy?</h1>
While various ways exist to perform a deep copy in Javascript, including creating a custom function that could maybe recursively do a shallow copy to emulate a deep copy, I usually go with a simple yet effective method. All we need are two methods already available to us out of the box.
 
<code>const johnMarks = [100, 98, 95, 99];</code>
<code>const a = {&nbsp;</code>
<code>&nbsp;&nbsp;&nbsp;name: 'John Smith',&nbsp;</code>
<code>&nbsp;&nbsp;&nbsp;marks: johnMarks</code>
<code>};</code>
<code>const b = JSON.parse(JSON.stringify(a));&nbsp;</code>
 
<code>console.log(a); // { name: 'John Smith', marks: [100, 98, 95, 99] };</code>
<code>console.log(b); // { name: 'John Smith', marks: [100, 98, 95, 99] };&nbsp;</code>
 
<code>johnMarks.push(100);&nbsp;</code>
 
<code>console.log(a); // { name: 'John Smith', marks: [100, 98, 95, 99, 100] };</code>
<code>console.log(b); // { name: 'John Smith', marks: [100, 98, 95, 99] };</code>
 
And there you have it — a neat deep copy performed by combining the JSON.parse() and JSON.stringify() methods. What is happening here is that first a string is constructed out of the source object, which is then used to create a new Object that gets stored in the second variable.
 
Note that while using this method for deep copying, ensure that the objects involved conform to <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/JSON" rel="noopener nofollow">JSON conventions</a>, to avoid unexpected errors. If they do not, you may have to look at other methods such as perhaps a custom function, as already mentioned.
 
 
That’s it then. In this article, we looked at the need for copying in Javascript, two different copying styles and a method each for implementing the copying styles. The methods illustrated and/or mentioned are by no means an exhaustive list, but simply methods I personally favour.
<figure> </figure>

Full Stack Web Application Developer

Javascript is a funny language, and the internet is filled with articles articulating this. In this article, we’ll be discussing a tricky bit in Javascript — copying.

A Tale of Two Copies

Alright, it’s time to come clean—we all feel the same way about music theory: who wants to study a bunch of stuffy old dead-guy music to learn what people did 200 years ago? There are so many other things to study that are more interesting, helpful, and fun, right? Well, not exactly. Even if you don’t find music theory fun, it’s our history, our tradition, and in essence, the platform upon which all of what we do is built.

Whether we realize it or not, music theory is essential to being a successful musician. It is all around us, built into the core of the Rock, Blues, Jazz, and Classical styles. What makes these styles distinguishable is how they utilize the basic elements of a theory. What would Blues be without the 12 bar form? What would Classical be without the big V-I cadence? Our culture is steeped in these traditions, and our ears have been trained to listen for, and even expect, music that follows these rules.

Now, here is why I think music theory is fun and even exciting. Because our music follows these rules, and even casual listeners unconsciously expect these conventions, we can create a unique musical experience by messing with the rules. Musicians playing with, stretching, and even breaking musical convention goes back to those stuffy old dead-guys. (If you don’t believe me, check out Haydn’s Surprise Symphony—the guy had a sense of humor!) They realized that keeping the audience engaged was important, and since they did not have fancy flashing lights, background projectors, or fireworks, they used theory.

The clever songwriter, composer, and even soloist learns the rules and conventions of music so that, at the precise moment, they can break the rules and do something so surprising, so unexpected, that they command immediate attention. It doesn’t matter if the audience realizes that the artist threw in a tri-tone substitute dominant, or switched modes, or even just pulled a deceptive cadence—they just know that, instead of the same old patterns, something new just happened. That, my fellow musicians, is the beauty of music theory.

So, the next time you listen to your favorite artist, whether it’s B.B. King, the Beatles, or even Franz Joseph Haydn, think about the moments that really catch your ear and draw you in. Odds are that it’s no accident—that surprising, unexpected, attention-grabbing moment that is the crux of every classic piece has its genesis in music theory.

Alright, it’s time to come clean—we all feel the same way about music theory: who wants to study a bunch of stuffy old dead-guy music to learn what people did 200 years ago? There are so many other things to study that are more interesting, helpful, and fun, right? Well, not exactly. Even if you don’t find music theory fun, it’s our history, our tradition, and in essence, the platform upon which all of what we do is built.
 
Whether we realize it or not, music theory is essential to being a successful musician. It is all around us, built into the core of the Rock, Blues, Jazz, and Classical styles. What makes these styles distinguishable is how they utilize the basic elements of a theory. What would Blues be without the 12 bar form? What would Classical be without the big V-I cadence? Our culture is steeped in these traditions, and our ears have been trained to listen for, and even expect, music that follows these rules.
 
Now, here is why I think music theory is fun and even exciting. Because our music follows these rules, and even casual listeners unconsciously expect these conventions, we can create a unique musical experience by messing with the rules. Musicians playing with, stretching, and even breaking musical convention goes back to those stuffy old dead-guys. (If you don’t believe me, check out Haydn’s Surprise Symphony—the guy had a sense of humor!) They realized that keeping the audience engaged was important, and since they did not have fancy flashing lights, background projectors, or fireworks, they used theory.
 
The clever songwriter, composer, and even soloist learns the rules and conventions of music so that, at the precise moment, they can break the rules and do something so surprising, so unexpected, that they command immediate attention. It doesn’t matter if the audience realizes that the artist threw in a tri-tone substitute dominant, or switched modes, or even just pulled a deceptive cadence—they just know that, instead of the same old patterns, something new just happened. That, my fellow musicians, is the beauty of music theory.
 
So, the next time you listen to your favorite artist, whether it’s B.B. King, the Beatles, or even Franz Joseph Haydn, think about the moments that really catch your ear and draw you in. Odds are that it’s no accident—that surprising, unexpected, attention-grabbing moment that is the crux of every classic piece has its genesis in music theory.

Whether we realize it or not, music theory is essential to being a successful musician.

A case for music theory

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