[python] How to create a file name with the current date & time in Python?

Here is a functional code (create file with success)

sys.stdout = open('filename1.xml', 'w')

Now I'm trying to name the file with the current date/time (I'm not an expert in Python)

filename1 = datetime.now().strftime("%Y%m%d-%H%M%S")
sys.stdout = open(filename1 + '.xml', 'w')

I want to write out a file name with the exact date and time, it is a xml file, that the program has already create, I just need to name the file. The above code is not working.

The error returned:

  File "./fix.py", line 226, in <module>
    filenames = datetime.now().strftime("%Y%m%d-%H%M%S")
AttributeError: 'module' object has no attribute 'now'

now is a class method in the class datetime in the module datetime. So you need

datetime.datetime.now()

Or you can use a different import

from datetime import datetime

Done this way allows you to use datetime.now as per the code in the question.

I'm surprised there is not some single formatter that returns a default (and safe) 'for appending in filename' - format of the time, We could simply write FD.write('mybackup'+time.strftime('%(formatter here)') + 'ext'

"%x" instead of "%Y%m%d-%H%M%S"

This one is much more human readable.

from datetime import datetime

datetime.now().strftime("%Y_%m_%d-%I_%M_%S_%p")

'2020_08_12-03_29_22_AM'

Here's some that I needed to include the date-time stamp in the folder name for dumping files from a web scraper.

# import time and OS modules to use to build file folder name
import time
import os 

# Build string for directory to hold files
# Output Configuration
#   drive_letter = Output device location (hard drive) 
#   folder_name = directory (folder) to receive and store PDF files

drive_letter = r'D:\\' 
folder_name = r'downloaded-files'
folder_time = datetime.now().strftime("%Y-%m-%d_%I-%M-%S_%p")
folder_to_save_files = drive_letter + folder_name + folder_time 

# IF no such folder exists, create one automatically
if not os.path.exists(folder_to_save_files):
    os.mkdir(folder_to_save_files)

import datetime

def print_time():
    parser = datetime.datetime.now() 
    return parser.strftime("%d-%m-%Y %H:%M:%S")

print(print_time())

# Output>
# 03-02-2021 22:39:28

This prints in an easy to read format -

import datetime

time_now  = datetime.datetime.now().strftime('%m_%d_%Y_%H_%M_%S') 

print(time_now)

Output: 02_03_2021_22_44_50

Change this line

filename1 = datetime.now().strftime("%Y%m%d-%H%M%S")

To

filename1 = datetime.datetime.now().strftime("%Y%m%d-%H%M%S")

Note the extra datetime. Alternatively, change your import datetime to from datetime import datetime