Python 错误 FileNotFoundError: [Errno 2] 没有这样的文件或目录

Question

I'm trying to make code and save the csv file named as filename = "title" + "today's date and time" + ".csv"

from datetime import date
import csv

filename = "title_" + str(date.today()) + ".csv"
f = open(filename, "w", encoding="utf-8-sig", newline="")
writer = csv.writer(f)

this seem to be working and file is saved as "title_2020-12-03.csv"

But I want to make file name with the time as well so I tried

from datetime import datetime
now = datetime.now()
today = now.strftime("%Y/%m/%d_%H:%M")

filename = "title_" + datetime.now().strftime("%Y/%m/%d_%H:%M") + ".csv"
f = open(filename, "w", encoding="utf-8-sig", newline="")
writer = csv.writer(f)

but this gives me an error

FileNotFoundError: [Errno 2] No such file or directory: 'title_2020/12/03_11:22.csv'

Any help would be appreciated, Thank you!

Answer 1

The problem with your approach is that the required filename will be recognized as a modified filepath to your file because of the slashes ( '/' ).

So in case of the name 'title_2020/12/03_11:22.csv' you won't find a file with the same name in the directory relative to the cwd of the execution, but rather the program will interpret the filename as a path and will try to look up the file '03_11:22.csv' in the 'title_2020/12/' directory.

Therefore you should use a different delimiter that doesn't confront with filepaths on your system. In general the safest is to use dashes or underscores.

Answer 2

Using dashes instead of slashes in the date it works:

from datetime import datetime
now = datetime.now()
today = now.strftime("%Y/%m/%d_%H:%M")

filename = "title_" + str(datetime.now().strftime("%Y-%m-%d_%H:%M")) + ".csv"
f = open(filename, "w", encoding="utf-8-sig", newline="")
writer = csv.writer(f)