Coursera Learner working on a presentation with Coursera logo and
Coursera Learner working on a presentation with Coursera logo and

In most cases, Python users start their journey by understanding how print() works.  The print function helps programmers write their one liners like hello world. Print can also be used for displaying formatted messages on the screen and for spotting bugs. That said, the print Python function has plenty more to offer and we will discuss all about it in this piece. 

Despite being quite unappreciated and slightly boring, print() offers a lot of things.  Before proceeding, it is worth keeping in mind that print() became a massive addition in Python 3 where it effectively replaced Python 2s older print.  

Python and Printing

Let us look at some Print python examples to learn the different ways of calling the print() function, which in programming language means becoming familiar with function signature. 

Print()

You do not have to pass arguments; however you still have to add empty parenthesis in this, which enables Python to execute this function instead of only referring to it by name. Doing so will create a newline character. This character will be invisible and create an blank like on your screen. You are free to call print() numerous times just like this for adding vertical space. It is quite similar to hitting the “Enter” button on the keyboard.

Newline Character

As men discussed earlier, not using arguments when calling print() creates a blank line. This line only contains the newline character. It is also worth keeping in mind that this line is not empty. Making use of the string literals in Python can help you visualize the elements in the line.

If you want to erase a newline character from Python, consider using the rstrip() method. Here is how this will look like. 

In most cases, it would be best to communicate a message towards the end user. Here is how you can make that happen. 

  • You can start by passing a string literal to print (): which will prompt a message saying (please wait while the program is loading)
  • You can extract the message and give it a relevant name to improve readability while ensuring you can reuse the code. 
  • Finally, you can pass expressions such as string concatenation for evaluating before you proceed to print the result.

Believe it or not, there are plenty of message formatting techniques in Python. Consider looking at the F strings present in Python 3.6 as the syntax they provide is arguably the most concise. Using the F strings ensures you do not make common mistakes like failing to add cast concatenated operands. Since Python is an incredibly strong language, it does not allow programmers to do things like the example below

Forcing numbers into strings is just plain wrong and does not make sense. Instead, it would be ideal to change the number into string for joining them. 

Python will always inform you about problems through a traceback unless you take care of such errors by yourself.

Standard Out and print()

If you are a programmer, you will be well aware that each program out there contains a text output area referred to as standard out, aka “stdout”. The print python function takes python data like strings and ints, printing the values towards standard out.

Calling standard out text in such a scenario means there are a group of lines in which every line happens to be a group of chars containing a newline char marking of ‘\n’ at the  end of every line. Despite what it may look like standard out isn’t too complicated. At its core, it is a text area that is shared be each code within a program. 

Standard out Terminal

Whenever someone runs a program in a terminal, they see standard out showing up right there. Let us look at an example of how to run the hello.py command inside the terminal.

$ python3 hello.py

hello there

how are you?

I am fine

$

The Python Print Function

The print python function essentially takes any amount of parameters after which it starts printing them in a singular line of text. Once this happens, these items are separately converted in the form of text, separated through spaces. It is also worth keeping in mind that there is a ‘\n’ towards the end. If called with 0 parameters, the print() command will only print ‘\n’.

The python source code writes text within a string using quotes such as “hello”, to ensure everyone is accustomed to see such forms. It is also worth keeping in mind that when you print a string, you will only print the string’s text data without any quotes. 

>>> print(‘Hello’)

Hello

 

Print and Return – Understanding the Correlation

Making use of the return command is undoubtedly the best way to return the results their respective caller. Also, using standard out is the secondary alternative for communicating data out. However, it is relatively simpler. Typically, standard out is in the form of text and shared in almost every function. 

Therefore, it would be best to utilize return values as the primary function testing and black box data output mechanism. Remember, standard out is essentially an alternative function output type and is often used for producing text output for users located in the terminal. 

Printing to File

In print python, printing in standard output is quite common. That said, the print() function is also ideal for printing to open files.  If you want to open a file to write, start by adding ‘w’ whenever you plan to call the open() function. Doing so will delete the file’s existing content, which is why you must be careful whenever you open for writing. Once the file is open, the elective file = parameter will guide the lines of text in the file rather than writing them in standard output.

 

Despite being a fundamental function, print python can be quite hard to understand. However, the information and tips discussed in this piece will provide you with a clearer idea, ensuring you can use print() effectively.