Syntax
One of the biggest advantages of Python is it's syntax. It is easy to read, write and understand.
In this article, I'm going to cover the below in brief.
- Comments - How to write single line and multi line comments in Python
- Variable definition - How to define variables in Python
- End of statement - How does Python identify the end of a statement
- Indentation - How integrated is indentation in Python syntax.
Comments
Comments are important part of any programming language. Python has two different ways of writing comments in the code.
- Multi-line comments
- Single-line comments
Multi-line comments can be written by mentioning three quotes (''') at the beginning and ending of the comment.
E.g.:
'''
Multiple lines of comments
Usually written at the start of a program/function
describing usage of the program/function
''' |
Multi-line comments are helpful when we need to write few lines of comments to describe about a block of code, a function or a program.
Single-line comments can be written with # and comment would end with End of line.
# Single line comments end with End of Line
print("Hello...") # Print Hello |
Variable Definition
Python is dynamically typed language and doesn't require variables to be defined with a specific data type. Python identifies the data type automatically based on the data passed into the variable.
E.g.:
a = 10 # Integer
b = "B" # String
|
End Of Statement
Unlike most of other programming languages, Python doesn't use/require a semicolon (;) to indicate end of statement. End of line (CR LF) is usually considered and end of statement.
E.g.:
As soon as end of line is detected, Python assumes the end of statement and considers the next line as the next statement.
We can also terminate a statement with semicolon (;). This usually helpful when we need to write multiple statements in a single line.
What if the statement is too big and has to extend beyond a line? Using '\' at the end of the line would help if a statement is going beyond single line.
c = "This is a big statement " \
"and has to extend beyond single line."
d = a/2 +\
100
|
Above two statements are equal to the below.
c = "This is a big statement and has to extend beyond single line."
d = a/2 + 100
|
This can also be done by enclosing with in parenthesis.
c = ("This is a big statement " +
"and has to extend beyond single line.")
d = (a / 2 +
100)
|
Indentation
Indentation is recommended in any programming language to make the code easy to understand. In Python, indentation is mandatory to indicate/write a block of code.
There is no restriction on how many spaces are to be used, but number of spaces need to be consistent in a block of code. But, 4 spaces are widely used.
# This function uses 4 blank spaces
def printA():
a = 10
print(a)
# This function uses 2 blank spaces
def printB():
b = "B"
print(b)
|
But, we cannot have different spaces in the same block of code.
# This function uses 4 blank spaces
def printA():
a = 10
print(a)
|
Having different number of spaces would cause the program to throw IndentationError (IndentationError: unindent does not match any outer indentation level)
A block of code doesn't necessarily be a function, it can also be a condition or loop.
# This function uses 4 blank spaces
def printA():
a = 10
b = 20
# This condition uses 2 blank spaces
if (a > b):
print("a is greater than b")
# Code with in else block uses 8 blank spaces
else:
print("b is greater than a")
|
In the above code,
- Statements with in printA function including if and else, are to follow the same indentation.
- Any code under if or else need to use the same indentation.
One thing to note here is, A block of code would always be preceded by colon (:).
Hope the above content has been of some help to you.
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