2.2. Python Syntax#

Python syntax is very simple and easy to learn. It is very similar to the English language. It can be executed in two ways:

  1. Interactive Mode

  2. Script Mode

2.2.1. Interactive Mode#

In interactive mode, you can type Python statements directly in the terminal and the interpreter will execute them immediately. To start the interactive mode, type python in the terminal. The following is the output of the interactive mode:

Python 3.6.5 (default, Apr 1 2018, 05:46:30)
[GCC 7.3.0] on linux

Example:

>>> 1 + 1
2

>>> print("Hello World")
Hello World

2.2.2. Script Mode#

In script mode, you can write Python statements in a file and then execute the file. To start the script mode, type python followed by the file name in the terminal. The following is the output of the script mode:

$ python hello.py
Hello World

2.2.3. Python Indentation#

Python uses indentation to indicate a block of code.

Python will give you an error if you skip the indentation:

# Example: Python Indentation

if 5 > 2:
print("Five is greater than two!")
# Python will give you an error if you skip the indentation:

  Cell In [1], line 4
    print("Five is greater than two!")
    ^
IndentationError: expected an indented block after 'if' statement on line 3

The number of spaces is up to you as a programmer, but it has to be at least one.

# Example: Python Indentation
if 5 > 2:
 print("Five is greater than two!")

# Example: Python Indentation
if 5 > 2:
    print("Five is greater than two!")

Five is greater than two!
Five is greater than two!

The spaces must be the same size in the same block of code, otherwise Python will give you an error.

# Example: Python Indentation
if 5 > 2:
    print("Five is greater than two!")
        print("Five is greater than two!")

  Cell In [3], line 4
    print("Five is greater than two!")
    ^
IndentationError: unexpected indent