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File Handling in Python

File handling in Python means creating, reading writing, and updating files through python We can handle files of various formats like *.txt, *.csv, etc.

Jump to specific sections

Opening a file
Reading a file
Writing in a file
Appending a file

Opening a file

The open() function allows to open files and then we can read, write or update their content as per our need. It takes two parameters.

The complete path of the file
The mode in which you want to open the file. By default, it is opened in 'r' mode if we don't specify any mode. (Optional)

Mode	Use
'r'	For reading the contents of the file only. Cannot change it.
'w'	For writing in the file. Overwrites any existing content of the file.
'a'	For appending at the end of the file. Does not overwrite the existing content of the file. If the file does not exist, then create a new file and then append it.
'x'	For creating a new file. If the file already exists, then it throws an error.
'+'	For both reading and writing a file.
't'	Opens the file in text mode.(default)
'b'	Opens the file in binary mode.


# If the file is present in the current directory, just specify its name.

f=open("myfile.txt", 'r')

# Otherwise, specify its full path along with the name of the file like - 

# f=open("C:\Users\HP\OneDrive\Desktop\myfile.txt",'r')

# When you open a file you must close it after your work is done.

f.close()

Alternate way of opening a file is by using the with keyword is given below. It automatically closes the file after the control goes out of the indent of the with block. Hence, this method is very useful.


with open("myfile.txt", 'r') as f:
    pass

Reading a file

The read() function helps to read the whole content of the file.


with open('myfile.txt', 'r') as f:
    print(f.read())

Output

Rapid Coders is a website where you will find courses, articles and projects related to various languages.
It is an all-rounder platform for Computer Science.

The readlines() function returns a list of all the lines present in the file.


with open('myfile.txt', 'r') as f:
    print(f.readlines())

Output

['Rapid Coders is a website where you will find courses, articles, and projects related to various languages.\n', 'It is an all-rounder platform for Computer Science.
']

The readline() function reads a line one by one from the file.


with open('myfile.txt', 'r') as f:
    while True:
        line=f.readline()
        if not line:
            break
        print(line)

Output

Rapid Coders is a website where you will find courses, articles, and projects related to various languages.

It is an all-rounder platform for Computer Science.

Writing in a file

To overwrite a file, first open it in write mode and then use the write() function to write content in it. Then again open the file in read mode and read its new content.


with open('myfile.txt', 'w') as f:
    f.write("Overwriting myfile.txt")

with open('myfile.txt', 'r') as f:
    print(f.read())

Output

Overwriting myfile.txt

The writelines() function is used to write multiple lines in the file.


lines=['Hello everyone\n','Hello rapid coders\n']
with open('myfile.txt', 'w') as f:
    f.writelines(lines)
        
with open('myfile.txt', 'r') as f:
    print(f.read())

Output

Hello everyone
Hello rapid coders

Appending a file


print("Before appending the contents of the file are :\n")
with open('myfile.txt', 'r') as f:
        print(f.read())

with open('myfile.txt', 'a') as f:
        f.write("What a beautiful day!")

print()

print("After appending contents of the file are :\n")
with open('myfile.txt', 'r') as f:
         print(f.read())

Output

Before appending the contents of the file are :

Hello everyone
Hello rapid coders

After appending contents of the file are :

Hello everyone
Hello rapid coders
What a beautiful day!