A video tutorial on R programming – The essentials

Here is a my video tutorial on R programming – The essentials. This tutorial is meant for those who would like to learn R, for R beginners or for those who would like to get a quick start on R. This tutorial tries to focus on those main functions that any R programmer is likely to use often rather than trying to cover every aspect of R with all its subtleties. You can clone the R tutorial used in this video along with the powerpoint presentation from Github. For this you will have to install Git on your laptop After you have installed Git you should be able to clone this repository and then try the functions out yourself in RStudio. Make your own variations to the functions, as you familiarize yourself with R.

git clone https://github.com/tvganesh/R-Programming-.git
Take a look at the video tutorial R programming – The essentials

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You could supplement the video by reading on these topics. This tutorial will give you enough momentum for a relatively short take-off into the R. So good luck on your R journey

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4. Programming Zen and now – Some essential tips -2
5. Fun simulation of a Chain in Android

Programming Zen and now – Some essential tips-2

This post is a follow-up to my earlier post – How to program – Some essential tips. In this post I expand on some of the ideas of my earlier post.

Programming means different things to different people. To some programming is a drudgery almost akin to manual labor, to others programming is an insurmountable mountain full of frustrations and disappointments while to others it is an intense problem solving and a creative activity. In my opinion programming can mean anything to you. It is your attitude towards coding that make it a chore, a daunting task or something really creative.

Here are some my insights on how to go about learning to code

Eyes wide open: People generally get frustrated when a piece of code that they wrote does not do what they intended it to do. In some cases the code snippet will do nothing when they were expecting final result, sometimes the code will crash or it will go into an infinite loop and drive the person nuts. (Let me assure you – I have been there, done that!) The usual reaction when this happens is anger and frustration where we generally tinker around with the code only to get the same result. Soon the emotions will progress from anger to hopelessness.

The first thing that one needs to while coding is to keep your ‘eyes wide open’. We tend to be guilty of ignoring the error messages that show up. Here one way to attack coding

a) Fully understand the ‘what’ of the problem. If there is an infinite loop or a core dump check after which point does it happen? If there is an execution error, what is the error trying to tell us?
b) Next look into ‘why’ the error occurred. You could either use debugger or insert appropriate print statements to take the offending code apart.
c) Thirdly think ‘how‘ you can address the situation. Make appropriate changes and re-run the code
d) Did it solve the issue.If yes, move forward. Otherwise go to step a)

Remember that we learn more from our programming mistakes more than when our code just ‘happens’ to work! Mistakes in our code make us to explain every part of the program

Changing times:

Times have changed. Programming Zen and programming now are worlds apart. In many ways, IDEs, Git, Google etc. have made the programmer’s life a lot easier

‘Git’ing from here to there: Here is a trick that I learnt fairly recently, though it should have occurred to me more than 2 years back. This is using Git judiciously for all programming tasks (Note: I am saying nothing new here!). I find it really useful in writing code with incremental changes. I create my initial code on the master and then test out incremental changes on a ‘new branch’ even for personal projects. Once I have proved a small increment works, I merge it with the ‘main’ branch. I again start working on the ‘new’ for the next incremental change followed by a merge to the master

The steps are

Make initial changes

1. git add .
2. git commit –m “ Initial changes’

Create a new branch
3. git checkout –b ‘new

Make incremental changes. Test.
4.git add .
5. git commit –m “Change 1”

Merge with the master
6.git checkout master
7. git merge new

Continue to work with ‘new’.
8 . git checkout new
9. Go to step 4)

This process can be continued till you get your final product. I find this extremely useful instead of just using an IDE to make code changes. Invariably you can run into a situation where you had something working some time back and in the next instant it is broken and you can’t figure out all the changes you made to the working code. This can be extremely frustrating. With Git you have a history of changes and you can switch to an earlier version of working code and start from there.

Rarely do I find a reason to have more than 1 branch

Here is a pictorial version of this

Taking help from Dr. Google: For most questions and errors that you encounter you will find others who have hit similar bugs. Just google it. You will more than surprised that others went down the exact same path that you are treading. Besides the internet is full of tutorials, blogs and articles on key aspects of programming

Explore the cave of Stack overflow: Spend time exploring Stack overflow. Stack overflow is replete with code snippets and questions that you wanted to ask. There is so much information out there. If you really don’t find an answer to your problem, post it in Stack overflow and you are bound to get an answer or a link to a similar question asked previously

Finally programming requires dollops of patience. Develop patience along with your skill in coding and soon programming will much more enjoyable to you.

1. Programming languages in layman’s language
2. The common alphabet of programming languages
3. How to program – Some essential tips
4. The mind of a programmer

How to program – Some essential tips

If one follows the arrow of time from the early 1980s to the present day, the number of programming problems have not only proliferated but have also become more difficult. Fortunately programming in itself has become more manageable with massive increases in computing horsepower, smarter tools and instant availability of information on the internet, typically with the click of a mouse.

Learning to program is no easy task, but can be done with the right mix of attitude, curiosity and interest. Becoming adept at programming, however, is something else. An interesting essay in this context is Peter Norvig’s ‘Teach yourself programming in 10 years’

Back in the 1980s when I wrote my first Fortran program on my college Mainframe, programming was a lengthy exercise, spanning several days.

My first program was to plot a sine wave of characters on a computer printout. Running this program required the following several steps

Enter the program on a teletype terminal and create a stack of Hollerith (punched) cards
Submit the stack of cards to the computer center
The computer center would do a batch execute in the evening on the Mainframe
God forbid, if your program has a syntax error. If you did find an error, go back to step 1, the next day.
Assuming everything is fine, the computer center would run your program and your output (printout) would be placed in the appropriate pigeon hole which you would need to pick up the next day.

The whole exercise to write a small-sized program could take anywhere between a couple of days to a whole week.

In the early 1990s things got a little better where one could code, compile, link and execute sitting at one’s desk. However while the programming itself got much simpler than before, certain tasks were still difficult. Till the late 90s programs of any sort had to be written using a regular text editor (vi , emacs etc.) You would then have to go through the process of compiling, linking and executing.

An angry compiler would typically spew forth venom at missing semi-colons, undeclared variables, and uninitialized values. This would happen till you are able to iron out all syntax errors. Then you would link, get undefined symbols and have to include appropriate libraries etc. And then finally you would execute your code, only to have it crash. The process of debugging would then start.

Luckily technology has made life a whole lot easier except for the last step where you could still run into an execution errors . In these days an IDE (Interactive Development Environment) like Eclipse will flag syntax errors, missing definitions/declarations etc. as you write your code. Moreover Eclipse can also indicate which libraries (imports) you would need to include in your package for it to build. The only missing step in IDEs of these days is the ability to predict possible execution errors in your program. I wouldn’t be surprised, if in future, like Microsoft Word, the IDE is able to tell you if a programming construct does not make sense.

So things have gotten a lot easier for the programmer. The following tips for are particularly useful as you progress along in programming

These days when you are learning a new programming language it is not necessary to know the language from cover to cover by reading a book. In those days when we learnt C it was necessary to know everything from bit structures, macros, pragma etc. The reason being that every syntax or execution error one had to rush to get the textbook and thumb through it for the answer. Not so, in these days of Google. You have the world’s library at your fingertips.
To get started it is necessary to learn just the most important programming constructs of the language say structure, class, car, cdr besides the usual suspects like loops, conditions and case constructs
Download and install an IDE for the language. In most case Eclipse will work
Try to write a simple program and test out your code.
To do any sort of programming these days you will necessarily need to make 3 friends
1. Google
2. Stackoverflow
3. Git & GitHub
Honing your Googling skills is very important. There are answers to almost any sort of programming problems out there. You would be surprised to know that there are many others who did exactly the same stupid mistake that you did out there. Also googling will take you to interesting tutorials, blogs, articles that discuss different aspects of the programming language and the problem you are trying to solve
Stackoverflow is really a God send to all programmers. There are so many questions on so many aspects of every programming language on earth there. If you spend time searching Stackoverflow you are bound to find answers, code snippets that you can readily use in your code
Post your questions in stackoverflow when you don’t find the answers there. You are bound to get quick answers. Thanks to the gamification of Stackoverflow (points, upvotes,badges etc) that has been created on Stackoverflow.
Git & GitHub: I would suggest that you download and install GitHub for Windows. This will provide you with version control on your desktop. You can modify code while being to switch back to an earlier version with Git. Read up a good tutorial on Git for Windows
Once you have working code you push it onto GitHub and share with other programmers

Now that you have the basic setup here are few other extremely important tips

The most important criteria for programming is ‘attitude’. Initially you are bound to get frustrated, angry, irritated etc. But it is necessary to look at the errors that you get with the right attitude. Know that an error is telling you something. Usually the answers to your mistake are in the ‘error message’ itself. Look at it closely and try to understand it. You will learn a lot more when you learn from errors than from copy-pasting from somebody else’s code, even if works right the first time around!
Make sure you do something different each time. As Einstein said “ If you keep doing the same thing, you will keep getting the same result’
There are different ways to debug your code. You could use the debugger and single step through the code and keep checking the values of the variables. I personally prefer print statements to localize where things are going wrong. I then try to narrow down the problem to a few lines of code and try to take it apart.

Hopefully the above tips are useful. Programming can be creative activity and will be indispensable in our future.

Above all have fun coding, there are so many possibilities these days!

Also see

1. Programming languages in layman’s language
2. The common alphabet of programming languages
3. The mind of the programmer
4. Programming Zen and now – Some essential tips -2

Programming Zen and now – Some essential tips-2

The mind of a programmer

Here is a short essay on the minds of the programmer and programming in general. Programming has been variously described as a science, an art, as black magic, as the work of craftsman etc. It is true, programming can be any or all of that described above. Programming in my opinion is going to become increasingly important in the years ahead. I would certainly advocate some knowledge and grasp of programming. There are many books that claim to teach programming anywhere between 3 to 21 days etc. This is not true. Learning to program is just the beginning of a never ending process. Here is a great piece by Peter Norvig – Teach yourself programming in 10 years.

Programming can be considered to be a language to express your thoughts on the solution to a problem. The ability to express in a programming language can vary between being simply pedestrian to being absolutely poetic! There are those who can wax eloquent in a programming language. In any case, programming is a means to an end, the end being the solution to a problem. Typically the solution to the problem, is expressed as an algorithm, which is then is coded through a programming language,. Programming can be a highly analytical and creative activity.

Programming is different from most other professions that I can think of. To get started all you need is a computer and an Integrated Development Environments (IDE) for e.g. Eclipse, which can be downloaded for free. The IDE can be used for writing code. There are no other associated costs.

Programming is also different from other professions in the sense, that you get your response immediately. For e.g. a painter can paint anything and imagine that he/she is the next Rembrandt or Picasso. A guitarist can create the most hideous sound and think he is Jimi Hendrix’s re-incarnation. Other professions like architects, civil engineers, scientists have to wait for several months to know whether they are in the right direction or not. It is not so with programming. You write code. When you compile it or execute it, the verdict is instantaneous. It is simply a “no go”, if you are wrong. There is no middle path. You are either right or you are wrong.

Having said that, I would like to look at the typical experiences of a programmer?

Tears, sweat and frustration: In the beginning programming is usually very intimidating and frustrating. In the initial stages when you grapple with the quirky syntax of the language, and try to formulate your thoughts around the problem, you will hit many speed bumps. It can be exhausting, tiring and nerve racking. There are no shortcuts in learning how to program. You have to go through the grind, memorize certain phrases and hope that your program works. Once you have you arms around the syntax, you are on your way to actually writing code that achieves something. Here again you will run into all sorts of problems, like loops that never end, inexplicable program crashes and mysterious run time errors etc. The early stages can be difficult and quite unforgiving. This phase requires patience to get through.

Feelings of megalomania: Someone with 5 to 7 years of programming experience knows most of the typical constructs by heart and will be able to quickly churn out programs, rather fast. This is a dangerous phase. Since you have been doing the same thing for a couple of years you are typically aware of the problems and can possibly tweak code to make it solve a slightly different problem. This is usually the stage when programmers start to experience a sense of megalomania. There are delusions of grandeur. You may remember the programmer shown in Golden Eye who keeps saying “I am invincible!” whenever he is able to solve a knotty problem. These programmers have the feeling that “Nothing is impossible”

Programming is a great leveler. Programming can be a great boost to your ego. When you are able to visualize a problem, strategize the solution and actually get it to work, it does wonders to your ego. Programming can really boost your self-esteem. But you should not just stick to your comfort zone and write code in exactly the same language in exactly the same domain. It really helps to move to a different language, preferably a different paradigm – for example a move from procedural (C) to Object Oriented (Java, C++) or from object oriented to functional (Lisp, Haskell). Similarly moving from Web programming to protocol design or from data communication to app design will do wonders. The shift to a new programming paradigm and new technical domain will put you on even keel. All your knowledge and expertise will evaporate when you move to a new domain. Moving around in technology will keep you more grounded. You will realize that there is still so much more to learn. There is yet another universe.

In other words, programming keeps you honest!

My journey of 25+ years as a programming has helped me to learn technology in all its flavors. More importantly I was able to learn about myself. I have seen it all. Sweat, tears, frustration, fear, anger, pride and ecstasy.

A few years back, once you learned the basics, if your work did not involve coding, there was not much to do. But these days you can really do some fun things. You can imagine any app you want and actually start to realize it. Who knows, your app may be the next block buster! I am certain all of us have ideas which we want to implement. Programming allows you to just that!

Programming really makes you exercise your grey cells. Who knows we will soon hear that research has proved that programming helps prevent Alzheimer’s and Parkinson’s disease.:-)

In any case, learning to program is one good thing.

Also see
1. Programming languages in layman’s language
2. The common alphabet of programming languages
3. How to program – Some essential tips
4. Programming Zen and now – Some essential tips -2