Python len of file

Python Check File Size

In this tutorial, you’ll learn how to get file size in Python.

Whenever we work with files, sometimes we need to check file size before performing any operation. For example, if you are trying to copy content from one file into another file. In this case, we can check if the file size is greater than 0 before performing the file copying operation.

In this article, We will use the following three methods of an OS and pathlib module to get file size.

os.path module:

• os.path.getsize(‘file_path’) : Return the file size in bytes.
• os.stat(file).st_size : Return the file size in bytes

Pathlib module:

os.path.getsize() Method to Check File Size

For example, you want to read a file to analyze the sales data to prepare a monthly report, but before performing this operation we want to check whether the file contains any data.

The os.path module has some valuable functions on pathnames. Here we will see how to use the os.path module to check the file size.

1. Important the os.path module This module helps us to work with file paths and directories in Python. Using this module, we can access and manipulate paths
2. Construct File Path A file path defines the location of a file or folder in the computer system. There are two ways to specify a file path.

Absolute path: which always begins with the root folder. The absolute path includes the complete directory list required to locate the file. For example, /user/Pynative/data/sales.txt is an absolute path to discover the sales.txt. All of the information needed to find the file is contained in the path string.

Relative path: which is relative to the program’s current working directory.

Example To Get File Size

import os.path # file to check file_path = r'E:/demos/account/sales.txt' sz = os.path.getsize(file_path) print(f'The size is', sz, 'bytes')

E:/demos/account/sales.txt size is 10560 bytes

Get File Size in KB, MB, or GB

Use the following example to convert the file size in KB, MB, or GB.

import os.path # calculate file size in KB, MB, GB def convert_bytes(size): """ Convert bytes to KB, or MB or GB""" for x in ['bytes', 'KB', 'MB', 'GB', 'TB']: if size < 1024.0: return "%3.1f %s" % (size, x) size /= 1024.0 f_size = os.path.getsize(r'E:/demos/account/sales.txt') x = convert_bytes(f_size) print('file size is', x)

os.stat() Method to Check File Size

The os.stat() method returns the statistics of a file such as metadata of a file, creation or modification date, file size, etc.

• First, import the os module
• Next, use the os.stat('file_path') method to get the file statistics.
• At the end, use the st_size attribute to get the file size.

Note: The os.path.getsize() function internally uses the os.stat('path').st_size .

import os # get file statistics stat = os.stat(r'E:/demos/account/sales.txt') # get file size f_size = stat.st_size print('file size is', f_size, 'bytes')

Pathlib Module to Get File Size

From Python 3.4 onwards, we can use the pathlib module, which provides a wrapper for most OS functions.

• Import pathlib module: Pathlib module offers classes and methods to handle filesystem paths and get data related to files for different operating systems.
• Next, Use the pathlib.Path('path').stat().st_size attribute to get the file size in bytes

import pathlib # calculate file size in KB, MB, GB def convert_bytes(size): """ Convert bytes to KB, or MB or GB""" for x in ['bytes', 'KB', 'MB', 'GB', 'TB']: if size < 1024.0: return "%3.1f %s" % (size, x) size /= 1024.0 path = pathlib.Path(r'E:/demos/account/sales.txt') f_size = path.stat().st_size print('File size in bytes', f_size) # you can skip this if you don't want file size in KB or MB x = convert_bytes(f_size) print('file size is', x)

Get File Size of a File Object

Whenever we use file methods such as read() or a write(), we get a file object in return that represents a file.

Also, sometimes we receive a file object as an argument to a function, and we wanted to find a size of a file this file object is representing.

All the above solutions work for a file present on a disk, but if you want to find file size for file-like objects, use the below solution.

We will use the seek() function to move the file pointer to calculate the file size. Let’s see the steps.

• Use the open() function to open a file in reading mode. When we open a file, the cursor always points to the start of the file.
• Use the file seek() method to move the file pointer at the end of the file.
• Next, use the file tell() method to get the file size in bytes. The tell() method returns the current cursor location, equivalent to the number of bytes the cursor has moved, which is nothing but a file size in bytes.

# fp is a file object. # read file fp = open(r'E:/demos/account/sales.txt', 'r') old_file_position = fp.tell() # Moving the file handle to the end of the file fp.seek(0, 2) # calculates the bytes size = fp.tell() print('file size is', size, 'bytes') fp.seek(old_file_position, 0)

Sumary

In this article, We used the following three methods of an OS and pathlib module to get file size.

os.path module:

• os.path.getsize('file_path') : Return the file size in bytes.
• os.stat(file).st_size : Return the file size in bytes

Pathlib module:

Did you find this page helpful? Let others know about it. Sharing helps me continue to create free Python resources.

About Vishal

I’m Vishal Hule, Founder of PYnative.com. I am a Python developer, and I love to write articles to help students, developers, and learners. Follow me on Twitter

Related Tutorial Topics:

Python Exercises and Quizzes

Free coding exercises and quizzes cover Python basics, data structure, data analytics, and more.

• 15+ Topic-specific Exercises and Quizzes
• Each Exercise contains 10 questions
• Each Quiz contains 12-15 MCQ

Источник

Get Length of File Using Python

To get the length of a file, or the number of lines in a file, you can use the Python readlines() and len() functions.

with open("example.txt","r") as f: print(len(f.readlines())) #Output: 101

When working with files, the ability to get different statistics about the file easily can be useful.

One such statistic is the length of a file. The length of a file is the number of lines in a given file.

We can get all lines in a file with the readlines() function, and then use the len() function to get the number of lines in the file.

Below is a simple example showing you how to get the length of a file in Python.

with open("example.txt","r") as f: print(len(f.readlines())) #Output: 101

How to Get File Size Using Python

Another common statistic, which may be helpful to know how to get, is the size of a file in bytes.

The Python os module has many great functions which help us interact with the operating system of our computer.

To get the size of a file in Python, you can use the os.path module getsize() function. getsize() returns the size of the file in bytes.

Below is a simple example showing how you can get the size of a file using Python.

import os print(os.path.getsize("C:/Users/TheProgrammingExpert/example.png")) #Output: 351

Hopefully this article has been useful for you to learn how to get the length of a file using Python.

Other Articles You'll Also Like:

• 1. Using Python to Get All Combinations of Two Lists
• 2. Sorting a List of Tuples by Second Element in Python
• 3. Touch File Python – How to Touch a File Using Python
• 4. pandas variance – Compute Variance of Variables in DataFrame
• 5. How to Check if String Contains Uppercase Letters in Python
• 6. How to Check if Number is Negative in Python
• 7. Draw Circle in Python Using turtle circle() Function
• 8. Find Magnitude of Complex Number in Python
• 9. pandas mad – Calculate Mean Absolute Deviation in Python
• 10. Python Random Uniform – Generate Random Numbers Uniformly in Range

About The Programming Expert

The Programming Expert is a compilation of a programmer’s findings in the world of software development, website creation, and automation of processes.

Programming allows us to create amazing applications which make our work more efficient, repeatable and accurate.

At the end of the day, we want to be able to just push a button and let the code do it’s magic.

You can read more about us on our about page.

Источник