This article was written in collaboration with my great friend, mentor and computer wizard Joaquín Tumas
First part here
The technology industry in general, and software development in particular, is a growing market and offers many job opportunities. Even so, the gateways are still more flexible than more traditional engineering careers, for example. According to a 2018 study, over 60% of IT recruiters agree that a college degree is not essential for professional success, while 45% consider bootcamps to be as valuable as a college degree in the field.
Moreover, programming allows you to work remotely and also freelance — this means that you can work without having to go through 4 or 5 years of college, and that you can strive for more work-life balance. That’s what I personally found when I left my career as a teacher for an IT job.
In the first part of our series, we learned the definition of programming, what can we use it for, and which languages are best suited to start programming. Today, we will look at some concepts that are common to most current programming languages, and which are going to be be helpful throughout this journey, whichever way you want to go. Let’s go back to our Python online interpreter and start coding.
What are variables?
A variable is a place in memory that we can name and store a value. It’s very useful to save values in code so that we can access and reuse them. In order to easily find them later, you need to give the variable a good name.
For example, we might create a variable name and store the value Mary, a variable phone and store the value 3333–5555, and so on. Whenever we need to use the name, we can use the name variable instead of the expression Mary. This allows us to change the value of the variable to Julie, and the code would be automatically updated. Thus, we would not have to replace the name Mary with Julie everywhere in the code, making our job faster, more practical and less prone to mistakes.
In our interpreter, try declaring some variables and using them to print information as in the following example:
Constants
A constant is a type of variable that holds a fixed value that cannot be changed. Like variables, we must name them, and this is usually done with capital letters, by convention. Some programming languages have ways of creating constants, others do not. In Python, they are not used much, but in Javascript they are.
Reserved Words
Reserved words are expressions that have a special and fundamental meaning in the source code. We cannot use these expressions to name variables. They depend on the language we are using, but generally include non-alphabetic characters like [] {},. ; ()! “” ‘’ and all math symbols + — * / = <>.
As homework, you can look up reserved words in the programming languages you know and also whether there are other rules for naming variables and constants. Leave a comment if you have any questions!
What types of data are there?
To store information in memory, the program needs to know the content and also the type of the data we are saving. Thus, a sentence such as “My name is Julie” would be of type string (text) and 12345 would be of some numeric type as integer (int). Each programming language has its types, but we will find similarities between them all.
Basic data types
These are the types we will use almost intuitively. In addition to string and integer mentioned previously, we also have boolean for true or false values, or char to represent a single character or letter.
Complex data types
Complex types represent more advanced concepts of languages. Among the most common, we can find the Array type that will represent a list of values or the Dictionary type that would represent a dictionary of words and their respective definitions. Let’s try creating an array in Python. In brackets, make a list of some types of cars you know (you can also create a list of countries, or fruits, you get the idea).
Operators
All programming languages aim to perform data operations. The elements that allow operations are called operators. In general, we have the following categories:
· Arithmetic: For arithmetic operations such as addition and subtraction. Ex: + — * /
· Assignment: To assign values for variables and constants, as in the “=” from previous examples. Do not mistake it for equal to, which is usually expressed as == or ===.
· Relational: To compare values. Ex: 5> 3. Returns a true value if 5 is greater than 3, and false if it’s less.
· Logical: To work with logical operations, this operator sets conditions for values that we know to be true or false and returns a result that must also be true or false.
Let’s look at an example of the logical operator or. I have two statements, and if at least one of them is true, my result will be true.
We see that the only case where the result is false is when both statements are false. In the last column, we’re putting another condition besides“or”. Try to make a similar table using the “and” operator. In this case, both statements must be true for the result to be true.
What are frameworks and why do we use them?
When we create complex programs with many elements and functions, we don’t have to reinvent the wheel and code everything from scratch. Frameworks and libraries give us tools to solve common software development problems — and save time and labor.
Library
A library is a set of tools or features that seeks to solve a specific problem. Websites we browse daily use libraries for images, animations and calendars. You can use different libraries to create your program, and they are flexible in how they relate to each other and to the original language.
Framework
On the other hand, the framework provides a solid foundation for your application, with some rules about how the program should be written. A framework does the work that multiple libraries together would do, solving many problems at once — in some cases even defining how files should be organized in folders.
A framework may be a little tough to learn at first, but in the long run it’s useful and safe — because it makes choices that have already been tested and approved by other developers. As homework, you can look up some popular frameworks in the programming language of your choice. We encourage you to learn the basics of this programming language before learning how to use a framework, but we think it’s important to know that they exist and that most applications today use some framework.
The complete series:
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