How to use Python print() function?
In the early days of your python learning, one function that you are going to use the most is the print() function. So, I have decided to add it in the opening chapter of this tutorial. In addition to the print function, you will be learning about commenting out and escape characters too.
As you would have seen in the last chapter, the basic syntax of using print function is:-
print()
Note- In python 2.7 you didn’t need to use the parenthesis but for python 3 and above, you must add parenthesis.
The syntax for the print() function is:-
print(object(s), sep=sep, end=end, file=file, flush=flush)
This could be quite overwhelming for a new-comer, but in the beginning, we will not be using most of the parameters above. But, you must know what each parameter means:-
1. object(s) : Any object(s) be it string, int, list, etc.
2. sep : how to separate the objects, Default='', Optional.
3. end : what to print at the end, Default='\n' (line end), Optional.
4. file : object with a write method, Default='sys.stdout', Optional.
5. flush : Boolean, True for output is flushed, False for buffered, Default ='False', Optional.
Normal usage
For printing out a string, you can use both ‘single quotes’ and “double quotes”.
print('This is printed using single quotes.')
print("This is printed using double quotes.")
The output will be:-
This is printed using single quotes.
This is printed using double quotes.
You can virtually print anything using the print() function, be it a string, int, boolean, list, dictionary, tuple etc. Create a file ‘print_example.py’ and add following lines to it:-
print(8)
print("A string")
print(True)
print(False)
print([1,2,3])
print((1,2,3))
print({'key1': 'data1', 'key2': 'data2' })
On running this file, you will get the following output:-
python print_example.py
The print() function can take more than one objects of the same or different kind. You can print a string with an int, a list with a tuple etc. by using a “,” (comma) in between. Each “comma” will add whitespace between the two objects.
print("hello", "world")
print("hello", 5)
print(3, "hello")
print(3, 5)
print([1, 2, 3], 5)
print("hello", "list", "tuple", "[]", "()", 5)
The output will be:-
How to print variables in python?
Till now, we were printing the values directly, but you can also print certain value using its variable name. In that case, you won’t be needing to add quotes to the variable name e.g.:-
a_number = 5
a_string = "A String"
print(a_number)
print(a_string)
The output will be:-
5
A String
Using escape character
The escape character in Python is backslash (\). It comes handy when you have to print a string which has quotes in itself e.g. if you need to print ‘I’ll be there.’ then using the single quotes will throw a syntax error:-
print('I'll be there')
File "<stdin>", line 1
print('I'll be there.')
^
SyntaxError: invalid syntax
Now you can correct this error in two ways, either by using a different kind of quotes or using the escape character:-
print("I'll be there")
print('I\'ll be there')
output:-
I'll be there
I'll be there
Multi-line printing
We can also use the print() function to do multi-line printing. The beauty of Python is that few things can be done in multiple ways but always there is one way which is convenient and more pythonic. So, I will quickly go through all the ways of doing it:-
1 Using the New line (‘\n’) special character
multiline_string = "Hi,\nI am a multi-line string.\nThanks!"
print(multiline_string)
output:-
Hi,
I am a multi-line string.
Thanks!
2 Using the separator(sep)
print("Hi,", "I am a multi-line string", "Thanks!", sep="\n")
output:-
Hi,
I am a multi-line string.
Thanks!
3 Using triple quotes- Alternatively, you can do it as under:-
multiline_string = """Hi,
I am a multi-line string.
Thanks!"""
print(multiline_string)
output:-
Hi,
I am a multi-line string.
Thanks!
How to add comments in a Python code?
While coding, some-time we need that interpreter should ignore certain lines of code, or we need to add a comment to our script (There will be a detailed chapter on comments). In python, the same can be done using a pound key (#) at the beginning of the line or using triple quotes (“”“) for multi-line commenting-out:-
# This is a comment
# print("This will not be printed")
print("This will be printed")
"""
This is a multi-line comment
print( "This will not be printed")
print( "This will not be printed")
print( "This will not be printed")
"""
Output:-
This will be printed
**Note:- I strongly recommend using logging for debugging your code. Check out our detailed post on logging.