How to Check File Size in Python

How do I check file size in Python?

You need the st_size property of the object returned by os.stat. You can get it by either using pathlib (Python 3.4+):

>>> from pathlib import Path
>>> Path('somefile.txt').stat()
os.stat_result(st_mode=33188, st_ino=6419862, st_dev=16777220, st_nlink=1, st_uid=501, st_gid=20, st_size=1564, st_atime=1584299303, st_mtime=1584299400, st_ctime=1584299400)
>>> Path('somefile.txt').stat().st_size
1564

or using os.stat:

>>> import os
>>> os.stat('somefile.txt')
os.stat_result(st_mode=33188, st_ino=6419862, st_dev=16777220, st_nlink=1, st_uid=501, st_gid=20, st_size=1564, st_atime=1584299303, st_mtime=1584299400, st_ctime=1584299400)
>>> os.stat('somefile.txt').st_size
1564

Output is in bytes.

can't get a file size in python

It is failing because of the line os.chdir(mypath). You don't need to chdir().

Assuming the path is correct and the file exists, it should work (print the file size) if you remove the os.chdir() statement.

Get file size, creation date and modification date in Python

https://docs.python.org/2.7/library/os.path.html#module-os.path

os.path.getsize(path) # size in bytes
os.path.ctime(path) # time of last metadata change; it's a bit OS specific.

Here's a rewrite of your program. I did this:

1. Reformatted with autopep8 for better readability. (That's something you can install to prettify your code your code. But IDEs such as PyCharm Community Edition can help you to do the same, in addition to helping you with code completion and a GUI debugger.)
2. Made your getListofFiles() return a list of tuples. There are three elements in each one; the filename, the size, and the timestamp of the file, which appears to be what's known as an epoch time (time in seconds since 1970; you will have to go through python documentation on dates and times).
3. The tuples is written to your text file in a .csv style format (but note there are modules to do the same in a much better way).

Rewritten code:

import os

def getListOfFiles(ruta):
    listOfFile = os.listdir(ruta)
    allFiles = list()
    for entry in listOfFile:
        fullPath = os.path.join(ruta, entry)
        if os.path.isdir(fullPath):
            allFiles = allFiles + getListOfFiles(fullPath)
        else:
            print('getting size of fullPath: ' + fullPath)
            size = os.path.getsize(fullPath)
            ctime = os.path.getctime(fullPath)
            item = (fullPath, size, ctime)
            allFiles.append(item)
    return allFiles

ruta = "FolderPath"
miArchivo = open("TxtPath", "w")
listOfFiles = getListOfFiles(ruta)
for elem in listOfFiles:
    miArchivo.write("%s,%s,%s\n" % (elem[0], elem[1], elem[2]))
miArchivo.close()

Now it does this.

my-MBP:verynew macbookuser$ python verynew.py; cat TxtPath
getting size of fullPath: FolderPath/dir2/file2
getting size of fullPath: FolderPath/dir2/file1
getting size of fullPath: FolderPath/dir1/file1
FolderPath/dir2/file2,3,1583242888.4
FolderPath/dir2/file1,1,1583242490.17
FolderPath/dir1/file1,1,1583242490.17
my-MBP:verynew macbookuser$

Python | HTTP - How to check file size before downloading it

If the server supplies a Content-Length header, then you can use that to determine if you'd like to continue downloading the remainder of the body or not. If the server does not provide the header, then you'll need to stream the response until you decide you no longer want to continue.

To do this, you'll need to make sure that you're not preloading the full response.

from urllib3 import PoolManager

pool = PoolManager()
response = pool.request("GET", url, preload_content=False)

# Maximum amount we want to read  
max_bytes = 1000000

content_bytes = response.headers.get("Content-Length")
if content_bytes and int(content_bytes) < max_bytes:
    # Expected body is smaller than our maximum, read the whole thing
    data = response.read()
    # Do something with data
    ...
elif content_bytes is None:
    # Alternatively, stream until we hit our limit
    amount_read = 0
    for chunk in r.stream():
        amount_read += len(chunk)
        # Save chunk
        ...
        if amount_read > max_bytes:
            break

# Release the connection back into the pool
response.release_conn()

how to get the size of csv file line by line?is thas possible using python

Something along the lines of this should work for getting the bytes per row/line:

(The +1 is for the newline)

import os

total_bytes = -1

with open("test.csv") as file_in:
    for line in file_in:
        bytes_on_this_line = len(line) + 1
        total_bytes += bytes_on_this_line
        
print(total_bytes)

print(os.path.getsize("test.csv"))

Output:

15
15

How can I get the file size from a link without downloading it in python?

To do this use the HTTP HEAD method which just grabs the header information for the URL and doesn't download the content like an HTTP GET request does.

$curl -I https://sra-download.ncbi.nlm.nih.gov/traces/sra46/SRR/005150/SRR5273887
HTTP/1.1 200 OK
Server: nginx
Date: Mon, 18 Mar 2019 16:56:35 GMT
Content-Type: application/octet-stream
Content-Length: 578220087
Last-Modified: Tue, 21 Feb 2017 12:13:19 GMT
Connection: keep-alive
Accept-Ranges: bytes

The file size is in the 'Content-Length' header. In Python 3.6:

>>> import urllib
>>> req = urllib.request.Request('https://sra-download.ncbi.nlm.nih.gov/traces/sra46/SRR/005150/SRR5273887', 
                                 method='HEAD')
>>> f = urllib.request.urlopen(req)
>>> f.status
200
>>> f.headers['Content-Length']
'578220087'

how to get file size without downloading it in python requests

Instead of using GET request, do HEAD request:

resp = requests.request('HEAD', "https://Whereever.user.wants.com/THEFILE.zip")

The HTTP HEAD method requests the headers that would be returned if the HEAD request's URL was instead requested with the HTTP GET method. In your case, where URL produces a large download, a HEAD request would read its Content-Length header to get the filesize without actually downloading the file.

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