Python I/O (input/output) and Import:

Python has built-in functions and modules for performing input/output (I/O) operations and importing modules.

Python I/O (Input/Output):

In Python, I/O (Input/Output) refers to how the program interacts with files, consoles, or other sources/sinks of data. 

Python has several built-in functions and modules that can be used for I/O operations.

Types of I/O Operations:

There are two types of I/O operations in Python:

• Text I/O: This is used for reading and writing text data, such as strings or characters.
• Binary I/O: This is used for reading and writing binary data, such as images, audio, or video.

Build-in Function for I/O:

Python provides the following built-in functions for I/O:

open() function:

This function is used to open a file and returns a file object. The open() function takes two arguments: the file name and the mode in which the file should be opened.

file = open("file.txt", "r")
The mode parameter can be:
"r": read-only mode
"w": write-only mode (will create the file if it does not exist)
"a": append mode (will create the file if it does not exist)
"x": exclusive creation mode (will fail if the file already exists)
"b": binary mode
"t": text mode (default)

close() function: 

This function is used to close a file after it has been opened. It should always be called after the file has been processed.

file = open("file.txt", "r")
# do something with the file
file.close()

read() function: 

This function is used to read data from a file. It takes an optional argument that specifies the number of bytes to read.

file = open("file.txt", "r")
data = file.read()
print(data)
file.close()

write() function:

This function is used to write data to a file. It takes a single argument, which is the data to be written.

file = open("file.txt", "w")
file.write("Hello, world!")
file.close()

readline() function: 

This function is used to read a single line from a file.

file = open("file.txt", "r")
line = file.readline(
print(line)
file.close()

writelines() function: 

This function is used to write a list of strings to a file.

file = open("file.txt", "w")
lines = ["Hello, world!", "This is a test file."]
file.writelines(lines)
file.close()

input() function: 

This function is used to read user input from the console.

name = input("Enter your name: ")
print("Hello, " + name)

Python also provides a few modules for more advanced I/O operations, such as csv, pickle, json, and socket. 

These modules provide a way to work with more complex data structures and protocols.

Python Import:

In Python, import statement is used to import modules, which are pre-defined or user-defined packages containing a set of functions, classes, or variables that can be used in a program. The syntax for the import statement is as follows:

import module_name

The module_name is the name of the module to be imported. Once the module is imported, its functions, classes, and variables can be accessed using the dot notation. For example:

import math
print(math.pi)

This will import the math module and access the value of pi constant from it.

How to import Functions in Python:

There are several ways to import modules in Python, which are as follows:

Importing specific attributes from a module:

It is possible to import specific attributes from a module using the from keyword.

from math import pi
print(pi)

This will import only the pi constant from the math module.

Importing a module with an alias:

It is possible to import a module with an alias using the keyword. For example:

import math as m
print(m.pi)

This will import the math module with an alias m.

Importing all attributes from a module:

It is also possible to import all attributes from a module using the * wildcard character. 

from math import *
print(pi)

This will import all the attributes from the math module, including the pi constant.

Importing a user-defined module:

In addition to built-in modules, Python also allows importing of user-defined modules. 

To import a module from a file, the file must have a .py extension and be located in the same directory as the script that is importing it. For example:

Suppose we have a file my_module.py with the following content:

def my_function():
    print("Hello, world!")

We can import this module into our main program as follows:

import my_module
my_module.my_function()

This will import the my_module module and call its my_function() function.

In addition to the built-in modules and user-defined modules, Python also provides a large number of third-party modules that can be installed using package managers such as pip. 

These modules can be used to perform a variety of tasks, including scientific computing, web development, and data analysis.