master-python-file-handling-just-few-hours

Introduction

As we all know a file is a collection of text that keeps the records of any event. File handling is essential for programmers as it allows users to perform operations on files such as read, write, append, etc.

File handling in python is super easy and it is important in any programming language because it stores the text data that can be used by programmers or programs. The basic steps in file handling are open a file, perform operations and close the file.

Python treats files as text or binary. Each line of code is terminated with a special character called EOL(End Of Line) characters such as a comma, newline, etc.

 

Opening a file in python

To access the file or to operate on the file we need to read that file first. Python has an open( ) function that is used to open a file. For demonstration, I will be using Jupyter Notebook. A file named “student.txt” is located in the current working directory.

Syntax

open(filename, mode)

filename: Name of  the file that needs to be accessed

mode: Mode in while a file is opened

 

Let’s take an example

file = open("student.txt","r")
print(file.name)

Output

student.txt

This shows that the file is opened successfully in reading mode and can only be used for reading purposes.

 

Modes of opening file in python

<r> ⇒ open file in read mode only

<rb> ⇒ open file in (read + binary) mode

<r+> ⇒ open file in (read + write) mode

<rb+> ⇒ open file in (read + write + binary) mode

<w> ⇒ open file in write mode

<wb> ⇒ open file in (write + binary) mode

<w+> ⇒ open file  in (read + write) mode

<wb+> ⇒ open file in (read + write + binary) mode

<a> ⇒ open file in append mode

<ab> ⇒ open file in (append + binary) mode

<a+> ⇒ open file in (append + read) mode

<ab+> ⇒ open file in (append + binary + read) mode

 

Closing a file in python

Once a file is opened it must be closed after operating in the file. Python has a close() function that is used to close the file.

Syntax

file_object.close()

 

Let’s take an example

file = open("student.txt","r")
print(file.name)
file.close()
print(file.closed)

Output

student.txt
True

Once the file is closed, we cannot perform any operations in the file.

 

Writing in a file

To write in a file python has a write() function. Also to perform the write operation file should be opened in write mode.

Syntax

file_object.write(string)

 

Let’s take an example

file = open("student.txt","w")
file.write("File handling in python is super easy.")
file.close()

 

To see the contents written in a file, we use  readline() or readlines()  function.

with open("student.txt") as f:
    print(f.readline())

Output

File handling in python is super easy.

 

Appending in file

Python has append() function to append contents in a file. This file should be open in append mode.

file = open("student.txt","a")
file.write("File handling is important.")
file.write("Programming with python is fun.")
file.close()

 

To display the contents of the file we need to open the file in read mode

read_file = open("student.txt", "r")
for line in read_file:
    print(line)
read_file.close()

Output

File handeling in python is super easy.File handling is important.Programming with python is fun.

 

Renaming a file

Renaming file needs rename() function of the os module

import os

os.rename("student.txt", "abc.txt")

 

The file named “student.txt” is changed to “abc.txt”.

with open("abc.txt", "r") as f:
    lines = f.readlines()
for line in lines:
    print(line)

Output

python is easy.

python is cool.

Codefires is growing.

 

Removing a file

To remove files from the system we need to use the remove() function from the os module.

os.remove("abc.txt")

 

Thus, a file named “abc.txt” is removed from the system. If we want to verify it, we can do the following,

try:
    with open("abc.txt") as f:
        print(f.readlines())
except:
    print("File doesnot exists")

Output

File doesnot exists

 

Conclusion

File handling seems to be very useful for any programming language. With python, file handling is easy to perform.

Files allow keeping records of big projects that assist programmers in better management of the project. Hence, file handling is very essential in python.

Happy Learning 🙂

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