Power to Build

Online Educational resources – 2


I am constantly seeking opportunities to learn, update my skills and if possible for free. There are plenty of resources available online including this blog (shameless plug :).

Don’t get me wrong about free, I do pay if the courses are required and good. But, when I am casually dabbling in some new technology, I want to get my feet wet with free resources if and when possible. For all I know, I may not even revisit :). Often times, free could mean “cheap” and sometimes even useless. So, you have to sift through the web. I am happy to share my experiences here.

I have posted about some of these online educational sites before. Recently, I found out about courses on IBM Developerworks. I have used their site before and their Redbooks. You can find a lot of mainframe as well as client/server topics there.

Their Developerworks learn page  is full of quality courses that are free. Here is the page with their Java courses. And they also sponsored the Big Data University  which offers several courses that are free. Here is their official pitch:

Learn Data Science With Our Data Science Fundamentals Learning Path

bigdatauniversity.com

Want to learn Data Science? Take our free Data Science Fundamentals learning path. You’ll learn data science fundamentals, tools, and even R programming.

 

As I mentioned earlier, Coursera, Edx, Udacity and Udemy are some of the other sites I use. These are called Moocs and reputed universities around the world offer highly technical courses on those sites. (For e.g., Udacity offers this nano-degree course on AI). Most of these offer the courses free to audit and fee for certificate option. So, you can try out the course before you fully invest in it.

And if you didn’t know, anyone who has premium membership on Linkedin, already have “Learning” option available to them. This is free. Linkedin aquired Lynda.com, an online training site and they seem to be integrating courses from Lynda into their Learning page. You can read more about it here:

http://www.pcworld.com/article/3123118/it-skills-training/linkedin-learning-finally-puts-lyndacoms-tech-training-courses-to-work.html

These continuing education sites are a boon to professionals working full time. These courses often cover complete topics but small enough to finish successfully. For e.g., a typical University level course may be broken down into 2 or 3 courses here. And you can take your course at your convenience, and if you miss the deadline for the classes, you can simply roll over to the next session that may start the following month. Remember the goal of these classes is to help you learn not to get a degree or put undue pressure.

I hope you will find these resources useful in adding value to your career path.

From C# To Java: Events


Java programming language tries to be everything for everybody and thus becomes a huge bag of goodies. But it could be confusing if not daunting, even for small tasks, to folks coming from other platforms.

Here the author talks vividly about how the Event Model in Java almost got him.

Scattered Code

I have been developing in C# for the last 3-4 years, and before that I was primarily a php coder. During one semester of my freshman year of college I did a little Java, but not much, and I have not done any since. I have decided to work on an N-Tier application in Java to give me a good project under my belt and show that I can use Java (and not just say to people that I can learn Java).

The problem with going from C# to Java is that the language is very similar. This is a problem because while I can figure out the language itself pretty easily, most “getting started” guideand tutorials are too beginner level to really be helpful. However, jumping straight into something such as a Spring framework tutorial or many other more high level tutorials can be pretty overwhelming, as they all…

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Regular Expressions (Regex or Regexp)


I use Regular Expressions (or Regex or Regexp as they are fondly called by programmers) a lot in my line of work as a programmer. This makes a lot of mundane editing tasks much  easier and even interesting. But, most of the programmers I know, either don’t know it or even if they heard of it, they are afraid to use it. So, here is my attempt at explaining this to everyone, whether you are a programmer or otherwise (user).

Real world Example 1
You all know the vowels. Remember?

A E I O U*

And remember the articles? There is a rule in English grammar to use articles while referring to nouns – one of a, an, the. General rule is, we have to use “an” when a noun begins with one of the above 5 vowels*. Remember that?

* I will ignore H in hour or honor for simplicity sake

For a non-native speaker of English, this may become confusing. That too, if their native languages don’t have the concept of using articles (they may just use “0ne” or just drop it altogether).

Imagine someone with less experience in articles wrote this flyer you asked for:

“A home insurance program is for the          regular joe like you and me. This home insurance program is a boon to the middle            class family                        to protect ­a asset. It’s a umbrella coverage that can cover a item or the complete home.

The insurance agency is upstairs. You take a elevator          and go up. You can talk to the advisor and get it all setup quickly. It is a operation, that is                  simple and easy to use, why wouldn’t you?”

All is well, you are about to print 100’s of this, but then you realize formatting is off. Look at the load of spaces in the middle. And yes, as a native speaker, those a’s in bold are so glaring to you (Flyer didn’t have the bold, let’s say the reader marked with thick pen). Now, you can go back to the computer and correct each entry there individually. On top of that, what if the company name is actually “Affordable Home Insurance” not just Home Insurance. You have to carefully change the “a”s there too.

This is only a few lines, so all is well. But, what if you are proof reading an author made this mistake randomly in the draft of his “first book” in English? Will you go back and look for it and correct one by one?

If you are a patterns kind of guy (or girl) you might think… Hmm. if only there is a way to tell the editor (or word processor) that you are looking for all the words that begin in a vowel and make sure any “a” before, be changed to “an”. And wherever there is a load of space, just replace with a single space. Bingo!! With couple of replacements, your entire document is proof-read.

You, my friend, just did a regular expression on me! This is possible and available in most modern editors.

(For the “an” problem you would have said a[ ]+([aeiouAEIOU])(.*). For finding multiple spaces, you could simply say [ ]+. And they could easily be replaced with An $1$2 and ” “ (single space) on regexr.com. More on these later).

Real world Example 2
For a sightly more complicated example, imagine you are working on RSVPs for a birthday party, you are arranging. You sort of created a simple questionnaire and sent out emails to people, like this:

Name:
Will you attend:
Will you be here for lunch:
How many:

And you got a lot of replies, say 100. You somehow managed to copy those into the below text file.

RSVP 1:

Name: Sam Varadarajan
Will you attend: Yes
Will you be here for lunch: Yes
How many: may be 2 or 3

RSVP 2:
Name: John Doe
Will you attend: X
Will you be here for lunch: –
How many: 1

RSVP 3:
Name: Jane Doe
Will you attend: YES
Will you be here for lunch:
How many: 2+

RSVP 4:
Name: Roboto Monstero
Will you attend: NO
Will you be here for lunch:
How many: 0

ETC

Then you realized, oh oh. It would have been nice to have them all listed out in a table? Like Excel?

# Name Coming Lunch? Howmany?
1 Sam Varadarajan Yes Yes 2 or 3
2 John Doe X 1
3 Jane Doe YES 2+
4 Roboto Monstero NO 0
Total (minimum) 5

You can go ahead sit there at your computer and copy each entry to the corresponding cell in Excel. Eventually, you will get there. What if you are doing this for a community project, say a marathon registration and there are literally 100s of people responding? (Of course, the questionnaire will be larger too).

You pattern matching girl will immediately think, if only I can tell the computer (editor or Word processing software you are using) to copy each RSVP (starts from RSVP and runs through How many: …) and collapse it to one line each. In doing so, pick up only numbers for some responses, consider YES/yes/Y/X as same. This is doable.

In all such scenarios, where you are dealing some (fuzzy?) text patterns and you want a tool/technique to blindly find and replace so as to standardize it, you are looking at Regular expression.

Or more formally, Regular expressions are a set of search patterns used to identify some text without specifically looking for it. Here is what Wikipedia has to say about them:

In theoretical computer science and formal language theory, a regular expression (sometimes called a rational expression)[1][2] is a sequence of characters that define a search pattern, mainly for use in pattern matchingwith strings, or string matching, i.e. “find and replace”-like operations.

If you have used PCs (or Unix) for a long while, you surely heard Star-dot-Star (*.*)? This means all the files. So, in its rudimentary form * represents all the characters in a string and thus is a regular expression. This pattern (*.*) then matches files like MyFirstDocument.doc and UsefulProgram.exe. Another character you might have come across would be question mark “?” which points to any single character.

There you have it. Armed with ? and *, you can start matching up words.

?_*.???
A_beautifulbook.doc

*+*=*
2+2=4

Note: * = all and ? = 1 char is only applicable in some commands, particularly in OS command prompt. As you enter the Regex world, forget these meanings. Here a dot (“.”) Represents single (any) character and dot-star (“.*”) represents many such characters.

All the above examples are somewhat of a real life (user level?) situation. But, we programmers face this type of question/challenge every day. We get files in one format, we need to reformat it, so the users could consume it in a more presentable format. Or we parse a log to make some sense out of it. One could use Regex for all such scenarios. In fact, almost all programming languages have some constructs to support this, with Perl, Python on one end, with fully integrated Regex capabilities to Java, C#, Javascript having libraries to support it.

With that you are now entering the exciting (or scary!)  world of Regular Expressions! Sort of an innocent looking English expression, but very powerful tool indeed. We will continue in the next blog post.

Contd…

to Part 2

Query function in Google Spreadsheets


anandexcels

Most versatile effective function and unique to Google Spreadsheets. I am documenting this function to understand it properly and for those who do not have programming background. I do not have previous experience with query. i will try to illustrate with examples.

If you have confusion and stuck some where please post your questions Google Docs forum at the following link https://productforums.google.com/forum/#!categories/docs/spreadsheets. There are experts in this area waiting for your questions.

Google Spreadsheet query is designed to be similar to SQL  with few exceptions. it is a subset of  SQL with a few feature of its own. if you are familiar with SQL it will be easy to learn.

The Syntax of the function is as follow:

QUERY(data, query, headers)

DATA: it can be columns(A:C open ranges) of data you want to query, range of cells such as A1:C10, result of function such as importrange, index etc.,

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Excel: Anchoring Cell


Excel is a great tool for analyzing and presenting data. You can create fancy and complex formulas to make it look nice and even create fancy reports. Like I posted in my last post a Doctor used it* to create a nice patient tracking system.

I create a lot of spreadsheets in my work as a developer everyday. I am not using it for business purposes, but more for analyzing data, sometimes presenting data in a fancier reports for users to see. This involves lot of formulas used in coloring, highlighting data.

If you are like me, you will type the formula once and copy and paste that on all cells. Here is an example:

2016-09-26-15_45_10-microsoft-excel-book1

Now, if you look at the formulas behind those cells (using Ctrl + Backtick – see here), you will see what I mean:

2016-09-26-15_50_23-microsoft-excel-book1

I typed the formula into D2, then I just copied and pasted the formula into D3, D4. Then Summed it up in D5.

This is fine for regular calculations where you have each line calculates based on the data in the same row.

What if you have a common cell that needs to be used in all calculations? Consider the below example, where the transactions are in a different currency and you want to calculate in USD. Instead of hard coding the Currency exchange rate, you put that in a Cell, so you can use it in various lines or even sheets.

2016-09-26-15_56_56-microsoft-excel-book1

Let’s look at the formulas behind (again by pressing control + back tick(`)):

2016-09-26-15_58_47-microsoft-excel-book1

 

What happened? I did the same thing like I did before, enter formula in C2 and copied and pasted into C3, C5. But the values there are 0. Why?

Hmm.. Now I see the problem. My conversion rate is in Cell B8. I correctly used this in my formula on the first line (C2). When I copied and pasted in to other cells, Excel naturally shifted the row numbers. Thus, my second value in the expression, in C3, C5, became B9, B11… which happen to be empty, thus the result = 0.

How do we avoid this? I typically go back and correct the formula, but that tends to be a tedious task, if you have a lot of such formulas on your spreadsheet. This is where anchoring comes in handy:

In Excel you can anchor a cell used in a formula by adding $ to it. Here is the modified formula and pasted values in other cells:

2016-09-26-16_02_28-microsoft-excel-book1

 

See that? When I added $ to B8 ($B$8), it anchored it. When I copied and pasted into other cells (C3, C5) it maintained that. And that did the job:

2016-09-26 16_05_10-Microsoft Excel - Book1.png

Voila! Oh yeah, to add anchor to a cell, you can type $ sign each time, or simply press F4 when you type a cell reference into a formula, as mentioned here. I love it when there is already a solution for a problem you run into. Don’t you?

Before closing, here are some terminologies:

Anchoring a cell reference gives you Absolute Reference – same reference is used anywhere on the spreadsheet. If you don’t anchor it, it gives you a Relative Reference – relative to the cell you are in. These are typically valid when used in a formula.


(*) I know the Doctor used Google Sheet there, but for practical purposes it works the same way Excel does.

Managing Patient Flow in a Busy Practice


I am currently doing a side project to build a Issue tracking/Dash board for our application. Current sheet we have is really dumb and needs to be updated manually all over the place and with mistakes. I have done a few other sheets with Google scripts. It’s really cool.

While researching on a good template to start with (really more for ideas), I stumbled on this post. It’s a nice use of a spreadsheet to show patient time tracking, visually with nice colors.

While I was generally impressed with the think-outside-the-box idea, I was completely taken aback, when I saw it was developed by an MD – that’s right folks, a medical doctor. Puts a lot of IT folks to shame!! Simply wow!

This solution uses Google Docs, so it’s free and easy to customize

Source: Managing Patient Flow in a Busy Practice

ATG Web Commerce


TechJavaWeb just posted this link to a great tutorial on ATG (now owned by Oracle).

Java and Ranga

ATG Web commerce is a powerful framework for building up eCommerce web application.
ATG requires the knowledge of intermediate level of Java/J2EE and object-oriented concepts.Currently it is owned by Oracle.

I would like to share a good blog which talks about Oracle ATG eCommerce Suite.

Source: http://learnoracleatg.blogspot.in/p/atg-e-commerce.html

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