How to create a file, write, read and append to file in python

In the post I will show how to create a File, Write, read and append in python.

Before that lets see the File Modes in Python

File Modes in Python
Mode	Description
'r'	Open a file for reading. (by default)
'w'	Open a file for writing. Creates a new file if it does not exist or deleates the file if it exists.
'x'	Open a file for exclusive creation. If the file already exists, the operation fails.
'a'	Open for appending at the end of the file without replacing it. Creates a new file if it does not exist.
't'	Open in text mode. (by default)
'b'	Open in binary mode.
'+'	Open a file for updating (reading and writing)

1. How to create a file

import os

file_name = 'ReddyInfoSoft.txt'

# Create File if it Does Not Exists

def create_file():

if not os.path.exists(file_name): # Check if file Exists or not

f = open(file_name, mode='w+')

f.close()

2. How to Write to File

# Write to the file

def write_2_file():

f = open(file_name, mode='w')

for i in range(9):

f.write('\nLine No:'+str(i))

f.close()

3. How to Append to File

def append_2_file():

f = open(file_name, mode='a+')

for i in range(9):

f.write('\nAppended Line No:'+str(i))

f.close()

4. How to read a file

# Read file (file can read only ones)

def read_file():

# reads entire file

f = open(file_name, mode='r')

print('Read All Lines\n')

data = f.read()

print(data)

f.close()

print('\nRead Line By Line\n')

f1 = open(file_name, mode='r')

lines = f1.readlines()

for line in lines:

print(line)

f1.close()

Combining All the parts will Look as shown Below.

import os

file_name = 'ReddyInfoSoft.txt'

# Create File if it Does Not Exists

def create_file():

if not os.path.exists(file_name): # Check if file Exists or not

f = open(file_name, mode='w+')

f.close()

# Write to the file

def write_2_file():

f = open(file_name, mode='w')

for i in range(9):

f.write('\nLine No:'+str(i))

f.close()

def append_2_file():

f = open(file_name, mode='a+')

for i in range(9):

f.write('\nAppended Line No:'+str(i))

f.close()

# Read file (file can read only ones)

def read_file():

# reads entire file

f = open(file_name, mode='r')

print('Read All Lines\n')

data = f.read()

print(data)

f.close()

print('\nRead Line By Line\n')

f1 = open(file_name, mode='r')

lines = f1.readlines()

for line in lines:

print(line)

f1.close()

if __name__ == "__main__":

create_file()

write_2_file()

append_2_file()

read_file()