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:
pathlib.Path('path').stat().st_size: Return the file size in bytes.
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.
- 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
- 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.txtis 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.
To maintain uniformity across the operating system, use the forward-slash (/) to separate the path. It’ll work across Windows, macOS, and Unix-based systems, including Linux. - Use os.path.getsize() function
Use the
os.path.getsize('file_path')function to check the file size. Pass the file name or file path to this function as an argument. This function returns file size in bytes. It raises OSError if the file does not exist or is inaccessible.
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 {file_path} size is', sz, 'bytes')Output:
E:/demos/account/sales.txt size is 10560 bytes
Get File Size in KB, MB, or GB
- First, get the file size using the getsize() function.
- Next, convert bytes to KB or MB.
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)Output:
file size is 10.3 KB
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_sizeattribute to get the file size.
Note: The os.path.getsize() function internally uses the os.stat('path').st_size.
Example:
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')Output:
file size is 10560 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_sizeattribute to get the file size in bytes
Example:
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)Output:
file size is 10.3 KB
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. Thetell()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.
Example:
# 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)Output:
file size is 10560 bytes
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:
pathlib.Path('path').stat().st_size: Return the file size in bytes.
