In this tutorial we are going to take a look at how you work with strings in Python. Now, any language worth its salt will have a number of options for working with text and Python is probably one of the best to use when it comes to processing text.

If you are new to programming in general you may be wondering what a string is. In terms of programming, a string is classed as any sequence of characters you can type with your keyboard, and let’s face it, if you want your application to be of any use to yourself or other users then you need it to tell you what it’s doing or to prompt you for an action, and that is where strings come into play.

They are your applications way of communicating with the user. Without the ability to enter and display text or software would be pretty useless.

So, how would you create a string in Python? Take a look at the following code:

It is hard not to wonder how current technology would have altered the events surrounding the tragic death of John F. Kennedy. On the afternoon of November 22, 1963, shots rang out in Dallas, TX, taking the life of JFK, one of the most beloved Americans. Given the same circumstances today, surely the advances in IT alone, would have drastically changed the outcome of that horrible day. Would the government have recognized that there was a viable threat looming over JFK? Would local and government agencies have been more prepared for a possible assassination attempt? Would the assortment of everyday communication devices assisted in the prevention of the assassination, not to mention, provided greater resources into the investigation? With all that the IT world has to offer today, how would it have altered the JFK tragedy?

As many conspiracy theories have rocked the foundation of the official story presented by government agencies, realization of the expansive nature of technology provides equal consideration as to how the event would have been changed had this technology been available during the time of the shooting. There were T.V. cameras, home 8mm recorders, even single shot-hand held cameras snapping away as the car caravan approached. Yet, there remains little documentation of the shooting and even less information pertaining to the precautions taken by officials prior to JFK's arrival. Theorists consider these possibilities along with how the world would have turned out had the great John F. Kennedynever been assassinated on that day.

I suspect that many of you are familiar with the term "hard coding a value" whereby the age of an individual or their location is written into the condition (or action) of a business rule (in this case) as shown below:

if customer.age > 21 and customer.city == 'denver'

then ...

Such coding practices are perfectly expectable provided that the conditional values, age and city, never change. They become entirely unacceptable if a need for different values could be anticipated. A classic example of where this practice occurred that caused considerable heartache in the IT industry was the Y2K issue where dates were updated using only the last 2 digits of a four digit number because the first 2 digits were hard-coded to 19 i.e. 1998, 1999. All was well provided that the date did not advance to a time beyond the 1900’s since no one could be certain of what would happen when the millennia arrived (2000). A considerably amount of work (albeit boring) and money, approximately $200 billion, went into revising systems by way of software rewrites and computer chip replacements in order to thwart any detrimental outcomes. It is obvious how a simple change or an assumption can have sweeping consequences.

You may wonder what Y2K has to do with Business Rule Management Systems (BRMS). Well, what if we considered rules themselves to be hard-coded. If we were to write 100s of rules in Java, .NET or whatever language that only worked for a given scenario or assumption, would that not constitute hard-coded logic? By hard-coded, we obviously mean compiled. For example, if a credit card company has a variety of bonus campaigns, each with their own unique list of rules that may change within a week’s time, what would be the most effective way of writing software to deal with these responsibilities?

Invoking an external command in Python is a two step process:

from subprocess import call
call(["ls","-1"])