Programming in python - Week 7,8

Programming in Python
Week-8 Content

Python Modules
● It is a file containing python definitions and statements.
● A module can define functions and variables.
● Grouping related code into module makes it easier to understand.
● The filename is the module name with suffix .py.
● The statements will be executed only once when the module is imported.
● Bunch of modules in a directory is a package.

import statement
● Can be used while importing a module.
● Can be used along with from to import specific items from a module.

Main function
● Not necessary in Python
● If the code file is run directly, __name__ is set to
__main__ internally
● If the file is imported as a module, __name__ will be equal
to module name instead of __main__ and thus, the code
inside main block will not be executed.

In-built string functions
● lower()
● upper()
● capitalize()
● center(length, character)
● count(value, start, end)
● endswith(value, start, end)
● expandtabs(tabsize)
● find(value, start, end)
● format(value1, value2...)
● index(value, start, end)
● islanum()
● isdecimal()
● isidentifier()
● islower()
● isspace()
● istitle()
● isupper()
● join(iterable)
● lstrip(characters)
● partition(value)
● replace(oldvalue, newvalue, count)
● rfind(value, start, end)
● rindex(value, start, end)
● title()
● swapcase()
● splitlines()

Error Handling
● Two features to handle any unexpected exceptions:
○ Exception Handling
○ Assertions

Exception Handling
● When exceptions occur, Python will normally stop execution and generate an
error message.
● This can be handled by using try-except-finally block.
● try - block that lets you test a part of the code for errors
● except - let’s you handle the exception
● finally - let’s you execute the code regardless of whether an error occurred or
not.
● If the try block raises an error, the except block will be executed.
● You can define as many except blocks as you want along with one try block.
● else block can be used to execute code if no exceptions are raised.
● You can also raise exceptions manually.

Standard exceptions
● Exception
● ArithmeticError
● OverflowError
● ZeroDivisionError
● AssertionError
● ImportError
● KeyboardInterrupt
● SyntaxError
● IndentationError
● TypeError
● IndexError
● NameError
● KeyError

Assertions
● The assert keyword is used when debugging code.
● Assertions are conditions which are always supposed to be true.
● It lets you check if a condition in code is true.
● You can specify messages in case it’s false but the code execution will end.

Configuration files in Python
● Config files help in creating the initial settings for the file.
● Configparser module can help in creation of config files.
● In Python, the configuration files have an extension of .ini
● It’s an inbuilt module and will be downloaded with Python3.
● Consists of multiple sections distinguished by [section_name]
● Each section contains key-value pairs separated by : or =
● You can then write or read the configuration file in the other files

Working with Files in Python
● File is a contiguous set of bytes used to store data.
● File is composed of 3 parts - (Header, Data, EOF)
● For accessing any file, a file path is required - string that represents the
location of the file. (Folder Path, File Name and File Extension)

Closing & Opening a File
● If you want to work with a file, the first action needed is to open it using open()
function.
● Closing a file after the work is done is essential or else the result could be
unwanted behavior.
● 2 ways to ensure that the file is closed properly:
○ try-finally block
○ with block
● Using with block, you need to specify a second argument on how do you plan
to use the file

A file can be opened in these 3 modes

Reading & Writing opened files
● .read(), .readline(), .readlines() can be used for reading content from a file.
● .write() and .writelines() can be used for writing content to a file.

Programming in python - Week 7,8

More Related Content

What's hot (19)

Similar to Programming in python - Week 7,8 (20)

More from Priya Nayak (6)

Recently uploaded (20)

Programming in python - Week 7,8