Python File IO Basics

- 
# Two types of memory
# 1. Volatile Memory : Data cleared as System Shut Down
# Example : RAM
# 2. Non-Volatile Memory : Data remains saved always.
# Example : Hard Disk

# File : In Non-Volatile Memory we store Data as File
# File may be text file,binary file(Ex - Image,mp3),etc.

# Different Modes of Opening files in Python

"""
"r" - Open file for reading - Default mode
"w" - Open a file for writing
"x" - Create file if not exists
"a" - Add more content to a file/ append at end in file
"t" - open file in text mode - Default mode
"b" - open file in binary mode
"+" - for update (read and write both)
"""

# Question of the tutorial:
# How to print docstring of func1()


# Answer : print(func1.__doc__)


######### INOpen(), Read() & Readline() For Reading File ##########


############ Open(), Read() & Readline() For Reading File #########

# file pointer(here f) returned by open function is used to read/write in file
# "rt" is default mode so it is optional to write
# Below is same as f = open("24. Tutorial.txt")

# f = open("24. Tutorial.txt", "rt")
# content = f.read()
# print(content)
# f.close()
# Good practice to close opened files
# Technically it is to frees/release all the resources
# using by file when it is open.

# Output : (as written in 24. Tutorial.txt)
# We are on a mission to transform and Optimize World with Indian Technologies.
# We will work hard.
# We will win.


## Reading in binary mode
# f = open("24. Tutorial.txt", "rb")
# content = f.read()
# print(content)
# f.close()

# Output : (read as binary)
# b'We are on a mission to transform and Optimize World with Indian Technologies.\r\nWe will work hard.\r\nWe will win.'


## Reading fixed length of characters
# f = open("24. Tutorial.txt", "rt")
# content = f.read(4)
# print(content)
# Output : We a

# Now file pointer ( f ) points to 5th character and starts reading from there.
# content = f.read(4)
# print(content)
# Output : re o

# f.close()

# Reading more than available characters
# f = open("24. Tutorial.txt", "rt")
# content = f.read(344555)
# It will print till available character
# print("1 :",content)
# Output :
# 1 : We are on a mission to transform and Optimize World with Indian Technologies.
# We will work hard.
# We will win.

# content = f.read(344555)
# Nothing left to read now
# print("2 :",content)
# Output :
# 2 :
# f.close()


## Printing character by character in each line

# f = open("24. Tutorial.txt", "rt")
# content = f.read()
# for line in content:
#     print(line)
# f.close()
# Output :
# W
# e

# a
# r
# e

# o
# n
# ...............

## Printing line by line using itreater in file

# f = open("24. Tutorial.txt", "rt")
# content = f.read()
# for line in f:
#     print(line)
# f.close()
# Output : Nothing because content has already read the file

# f = open("24. Tutorial.txt", "rt")
# content = f.read()
# for line in f:
#     print(line)
# f.close()
# Output : (print by default give a backslash end character and file also have new line charcter when we write next line in file)
# We are on a mission to transform and Optimize World with Indian Technologies.

# We will work hard.

# We will win.

# f = open("24. Tutorial.txt", "rt")
# content = f.read()
# for line in f:
#     print(line,end="")
# f.close()
# Output : (print bydefault give a backslash end character)
# We are on a mission to transform and Optimize World with Indian Technologies.
# We will work hard.
# We will win.

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