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Strange behavior when trying to create and write to a text file on macOS [duplicate]

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Convert UTF-8 with BOM to UTF-8 with no BOM in Python
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I'm opening a plain text file, parsing it, and adding different lines to existing, empty string variables. I add these variables into a new variable that is a multi-line fstring. Trying to write the data to a new text file is not behaving as expected.
Reading the original file works fine. Text is properly parsed, variables populated.
The multi-line fstring variable seems fine. Prints normally. Even tried formatting it different ways which I show below.
When writing to a new file, that's where the strangeness starts. I've tried 2 ways:
Straight coding the open function with w or w+
Adding the above to a function and using that inside main()
The file is saved to disk with the correct name. Trying to double-click open in Finder produces nothing. Right-click to open produces nothing. Trying to move to trash with command+delete gives an error:
It sounds like the file goes to trash, but as the file disappears from the folder a new one is created with the same name in its place.
If I try to open in TextMate via File > Open, it opens as a blank file with no errors.
Since I can't get rid of the file, I have to delete the directory and create the directory again with the same name, or force delete in Terminal using rm. Restarting the system does not help. Relaunching Finder does nothing. Saving text files from other apps works fine. Directory is chmod 755.
If I copy an existing text file into the output directory, rename it to what the file is expected to be named, and let python overwrite the contents, it doesn't work either. The file modification date changes (and I see the file "blink" in Finder) but the contents remain the same. However, the file is not corrupted and opens normally.
If I do the same but delete the text inside of the copied file first, then run the script, python writes no data to the file, I can't open it by double-clicking on it, and I get error -43 again with the odd non-trashing behavior.
The strangest thing is this: if I add another with open() at the end of the script, and open the file that was just created and supposedly written to, and print its contents, the contents print. It's like when the script ends the file contents are being removed or its being corrupted somehow. Tried to close the file inside the script even though it's not needed, but same behavior persists.
Code:
Here's the code for writing:
FORMAT='utf-8'
OUTPUT_DIR = '/Path/To/SaveFolder'
# as a function
def write_to_file(content, fpath, name):
the_file = os.path.join(fpath, name)
with open(the_file, 'w+', encoding=FORMAT) as t:
t.write(content)
def main():
print(f" Writing File...\n")
filename = f"{pcode}_{author}_{title}_text.txt"
write_to_file(multiline_var, OUTPUT_DIR, filename)
# or hard coded in main()
def main():
print(f" Writing File...\n")
filename = f"{pcode}_{author}_{title}_text.txt"
the_file = os.path.join(OUTPUT_DIR, filename)
with open(the_file, 'w+', encoding=FORMAT) as t:
t.write(multiline_var)
I have tried using w w+ wt and wt+ and with and without encoding='utf-8'
Here is an example of multi-line fstring variable:
# using triple quotes
multiline_var = f"""
[PROJ-{pcode}] {full_title} by {author}
{description}
{URL}
{DIVIDER_1}
{TEXT_BLURB}
Some text here and then {SOME_MORE_TEXT}"
{DIVIDER_1}
{SOME_LINK}
"""
# or inside parens
multiline_var = (
f"[PROJ-{pcode}] {full_title} by {author}\n"
f"{description}\n\n"
f"{URL}\n"
f"{DIVIDER_1}\n"
f"{TEXT_BLURB}\n\n"
f"Some text here and then {SOME_MORE_TEXT}\n"
f"{DIVIDER_1}\n\n"
f"{SOME_LINK}"
)
Using exiftool on the text file shows the following, so it looks the data is there but must be corrupted:
File Size : 1797 bytes
File Modification Date/Time : 2021:12:31 15:55:39-05:00
File Access Date/Time : 2021:12:31 15:58:13-05:00
File Inode Change Date/Time : 2021:12:31 15:55:39-05:00
File Permissions : -rw-r--r--
File Type : TXT
File Type Extension : txt
MIME Type : text/plain
MIME Encoding : utf-8
Byte Order Mark : No
Newlines : Unix LF
Line Count : 55
Word Count : 181
Not sure what I'm doing wrong. VScode shows no syntax errors in the script. There are no errors in Terminal when running the script. Have I made some simple mistake in the above code? Maybe the fstring variable is causing a problem?

Thanks to #bnaecker for leading me to the solution to this problem.
It appeared that when creating/writing to a text file with a long name, Python can corrupt it. Not sure why, as I save long names for images with Python image libraries all the time. Using a short name like "MyFile.txt" it worked just fine, but that was a red herring.
I have updated this post with my journey to the final solution for using the long names that are needed for my project, though I'm not sure why the problem exists.
First Attempts:
So far creating using a short name and then renaming to a long one.... attempts have failed. I did notice that python is locking the file it creates and never unlocks it. Not sure if this is the problem. Setting chflags with os.system('chflags nouchg') command does not work, not even with sudo, and not even in the Terminal doing it manually.
Using os.rename() in Python corrupts the file
Using os.system('mv oldFile.txt newFile.txt') corrupts the file
Manually using mv command in Terminal corrupts the file
Manually changing the filename in the Finder does not (wtf?)
I kept looking for workarounds but nothing did the job.
Round 2:
Progress!
After much tinkering, I discovered a hidden character inside the file. I ran cat /path/longfilename.txt in Terminal, selected and copied the output and pasted into VScode. Here is what I saw:
Somehow a hidden character is getting into the project code number.
Pasting it into a Unicode search engine it came up as a ZERO WIDTH NO-BREAK SPACE also known in Unicode as EF BB BF. However, when pasting this symbol into TextMate it shows up as <U+FEFF> which is?...
The Byte Order Mark!
Opening a normal utf-8 text file in a hex editor also shows the files starting with EFBBBF for the BOM.
Now, the text file being read and parsed at first has no blank lines to start the file, so I added a line break, and also tried adding some spaces. This time when writing the file I could open it, however, after sending it to the trash, the same behavior occurred and the file was broken again. It seems that because other corrupted versions were in the trash, it added the symbol back to the file name for some reason.
So what appears to be happening, for whatever reason, when Python opens the text file I'm parsing that has no line break at the top, it seems to be grabbing the BOM from the file and adding that to the first variable which is grabbing the first line of the text file. Since that text is a number code that starts the file name, the BOM symbol is being added to the file name as well as the code inside the text file.
Just... wow
The Current Solution:
I have to leave a blank line at the start of the text file that I'm opening and parsing and a simple line break won't do it. I have no idea why this is. I added some spaces for good measure because randomly the BOM would be added to the variable and filename again. So far (knock on wood) as long as the first line of that initial file has some spaces and then a line break, and previous corrupted files have been deleted from the trash, a long file name can be used for all the files I'm creating and writing to without any problems.
This corruption even persists if I remove the encoding flag from both of the open functions I'm using (one to read and parse, the other to create and write).
If anyone knows why this is happening, please share. I've never seen it mentioned before. I'm not sure if it's a python 3.8 bug, a mac OS bug, the way TextMate wrote the original file, or a combination of these.
Correct Solution:
Thanks to #tripleee for the proper way to handle this, as I don't remember seeing this before, though I haven't been using python for very long.
In order to ignore the BOM, reading in the text file to be parsed with an encoding='utf-8-sig' does the job. Seems to be why it exists. :)
Problem solved.

Open an external file in python

x = open('Homework','r')
print(x.name)
x.close()
I got this error when I run the code.
File "C:/Users/LENOVO/Desktop/pythonhome/tobechanged.py", line 16, in <module>
x = open('Homework','r')
FileNotFoundError: [Errno 2] No such file or directory: 'Homework'
SO I tried to type the full path
x = open('C:\Users\LENOVO\Desktop\pythonhome','r')
print(x.name)
x.close()
I got an Unicode error.
btw I'm using windows.

As the comments mentioned, it's usually good to type out the full path to the file, because running a script in IDLE, for example, can cause Python to search for the file in a directory that you are not intending. The reason you got the Unicode error is because you are using a special character, the backslash (\) which starts something known as an escape sequence. Escape sequences allow coders to specify special characters, like the newline character: \n. You can read more about these in Python's docs here
You have to either use a raw string (a string preceded with r, like this r'C:\Users\...'), or escape these characters with double backslashes, like this: C:\\Users\\....
Additionally, you need to specify the extension for the Homework file, otherwise the file system won't be able to find the file you are referring to, resulting in the FileNotFoundError you encountered. As #tdelaney mentioned, these extensions may be hidden by default in Windows Explorer.
Also, the recommended way in Python to open files is using the with statement, as this handles closing the object for you. Here is a sample (assuming that the extension of the Homework file is .txt):
with open('C:\\Users\\LENOVO\\Desktop\\pythonhome\\Homework.txt', 'r') as x:
print(x.name)

It is because you are forgetting the extension to the file (the ending of it). For example, if you have a text file that is named Homework, you would include it in like this
open(r'Homework.txt','r')
For this example, it must be in the same directory as your script. If you wanted to open a file outside of your scripts directory, you would have to find the full path of it. Here is an example of the Homework.txt file in my downloads folder.
open(r'C:\Users\USER\Downloads\Homework.txt','r')
You can also see in this code I use an r infront of the path. This tells Python the expression is a raw string and escape sequences are not parsed.

Python for Data Analysis, Chapter 2, first example

I'm following along with the examples in a translated version of Wes McKinney's "Python for Data Analysis" and I was blocked in first example of Chapter 2
I think my problem arose because I saved a data file in a wrong path. is that right?
I stored a file, usagov_bitly_data2012-03-16-1331923249.txt, in C:\Users\HRR
and also stored folder, pydata-book-mater, that can be downloaded from http://github.com/pydata-book in C:\Users\HRR\Anaconda2\Library\bin.

Depends.
You might change the location you save your File or eddit the path you give to your code in Line 10. Since you're yousing relativ Paths i guess your script runs in C:\Users\HRR\Anaconda2\Library\bin, which means you have to go back to C:\Users\HRR or use an absolute Path ... or move the File, but hell you don't want to move a file every time you want to open it, like moving word files into msoffice file to open it, so try to change the Path.
And allways try harder ;)

In python open() will open from the current directory down unless given a full path (in linux that starts with / and windows <C>://). In your case the command is open the folder ch02 in the directory the script is running from and then open usagov_bitly_data2012-03-16-1331923249.txt in that folder.
Since you are storing the text file in C:\Users\HRR\usagov_bitly_data2012-03-16-1331923249.txt and you did not specify the directory of the script. I recommend the following command instead open(C:\\Users\\HRR\\usagov_bitly_data2012-03-16-1331923249.txt)
Note: the double \ is to escape the characters and avoid tabs and newlines showing up in the path.

Cannot read in files

I have a small problem with reading in my file. My code:
import csv as csv
import numpy
with open("train_data.csv","rb") as training:
csv_file_object = csv.reader(training)
header = csv_file_object.next()
data = []
for row in csv_file_object:
data.append(row)
data = numpy.array(data)
I get the error no such file "train_data.csv", so I know the problem lies with the location. But whenever I specify the pad like this: open("C:\Desktop...etc) it doesn't work either. What am I doing wrong?

If you give the full file path, your script should work. Since it is not, it must be that you have escape characters in your path. To fix this, use a raw-string to specify the file path:
# Put an 'r' at the start of the string to make it a raw-string.
with open(r"C:\path\to\file\train_data.csv","rb") as training:
Raw strings do not process escape characters.
Also, just a technical fact, not giving the full file path causes Python to look for the file in the directory that the script is launched from. If it is not there, an error is thrown.

When you use open() and Windows you need to deal with the backslashes properly.
Option 1.) Use the raw string, this will be the string prefixed with an r.
open(r'C:\Users\Me\Desktop\train_data.csv')
Option 2.) Escape the backslashes
open('C:\\Users\\Me\\Desktop\\train_data.csv')
Option 3.) Use forward slashes
open('C:/Users/Me/Desktop/train_data.csv')
As for finding the file you are using, if you just do open('train_data.csv') it is looking in the directory you are running the python script from. So, if you are running it from C:\Users\Me\Desktop\, your train_data.csv needs to be on the desktop as well.

How do I allow opening of files that have Unicode characters in their filenames?

I have this Python script here that opens a random video file in a directory when run:
import glob,random,os
files = glob.glob("*.mkv")
files.extend(glob.glob("*.mp4"))
files.extend(glob.glob("*.tp"))
files.extend(glob.glob("*.avi"))
files.extend(glob.glob("*.ts"))
files.extend(glob.glob("*.flv"))
files.extend(glob.glob("*.mov"))
file = random.choice(files)
print "Opening file %s..." % file
cmd = "rundll32 url.dll,FileProtocolHandler \"" + file + "\""
os.system(cmd)
Source: An answer in my Super User post, 'How do I open a random file in a folder, and set that only files with the specified filename extension(s) should be opened?'
This is called by a BAT file, with this as its script:
C:\Python27\python.exe "C:\Programs\Scripts\open-random-video.py" cd
I put this BAT file in the directory I want to open random videos of.
In most cases it works fine. However, I can't make it open files with Unicode characters (like Japanese or Korean characters in my case) in their filenames.
This is the error message when the BAT file and Python script is run on a directory and opens a file with Unicode characters in its filename:
C:\TestDir>openrandomvideo.BAT
C:\TestDir>C:\Python27\python.exe "C:\Programs\Scripts\open-random-video.py" cd
The filename, directory name, or volume label syntax is incorrect.
Note that the filename of the .FLV video file in that log is changed from its original filename (소시.flv) to '∩╗┐' in the command line log.
EDIT: I learned that the above command line error message is due to saving the BAT file as 'UTF-8 with BOM'. Saving it as 'ANSI or UTF-16' shows the following message instead, but still does not open the file:
C:\TestDir>openrandomvideo.BAT
C:\TestDir>C:\Python27\python.exe "C:\Programs\Scripts\open-random-video.py" cd
Opening file ??.flv...
Now, the filename of the .FLV video file in that log is changed from its original filename (소시.flv) to '??.flv.' in the command line log.
I'm using Python 2.7 on Windows 7, 64-bit.
How do I allow opening of files that have Unicode characters in their filenames?

Just use Unicode literals e.g., u".mp4" everywhere. IO functions in Python will return Unicode filenames back if you give them Unicode input (internally they might use Unicode-aware Windows API):
import os
import random
videodir = u"." # get videos from current directory
extensions = tuple(u".mkv .mp4 .tp .avi .ts .flv .mov".split())
files = [file for file in os.listdir(videodir) if file.endswith(extensions)]
if files: # at least one video file exists
random_file = random.choice(files)
os.startfile(os.path.join(videodir, random_file)) # start the video
else:
print('No %s files found in "%s"' % ("|".join(extensions), videodir,))
If you want to emulate how your web browser would open video files then you could use webbrowser.open() instead of os.startfile() though the former might use the latter internally on Windows anyway.

The error when running the BAT file is because the BAT file itself is saved as "UTF-8 with BOM". The "" bytes are not a corrupted filename, they are the literal first bytes stored in the BAT file. Re-save the BAT file as ANSI or UTF-16, which are the only encodings supported for BAT files.

Either use Unicode literals as described by J. F. Sebastian, or use Python 3, which always uses Unicode.
(For Python 3, your script will need a minor modification: print is a function now, so you have to put parentheses around the parameter list.)

please familiarize yourself to add # -*- coding: utf-8 -*- in your source code,
so python understanding about your unicode.