Copying files raises a SyntaxError can't decode bytes - python

I'm trying to code a short program that makes backups of a folder whenever I run it. Currently it's like this:
import time
import shutil
import os
date = time.strftime("%d-%m-%Y")
print(date)
shutil.copy2("C:\Users\joaop\Desktop\VanillaServer\world","C:\Users\joaop\Desktop\VanillaServer\Backups")
for filename in os.listdir("C:\Users\joaop\Desktop\VanillaServer\Backups"):
if filename == world:
os.rename(filename, "Backup " + date)
However I get an error:
SyntaxError: (unicode error) 'unicodeescape' codec can't decode bytes in position 2-3: truncated \UXXXXXXXX escape
and I can't figure out why (according to documentation, I think my code is properly written)
How can I fix this/do it in a better way?


In Python, \u... denotes a Unicode sequence, so your \Users directory is interpreted as a Unicode character -- not with very much success.
>>> "\u0061"
'a'
>>> "\users"
File "<stdin>", line 1
SyntaxError: (unicode error) 'unicodeescape' codec can't decode bytes in position 0-1: truncated \uXXXX escape
To fix it, you should escape the different \ as \\, or use r"..." to make it a raw string.
>>> "C:\\Users\\joaop\\Desktop\\VanillaServer\\world"
'C:\\Users\\joaop\\Desktop\\VanillaServer\\world'
>>> r"C:\Users\joaop\Desktop\VanillaServer\world"
'C:\\Users\\joaop\\Desktop\\VanillaServer\\world'
Don't do both, though, or else they will be escaped twice:
>>> r"C:\\Users\\joaop\\Desktop\\VanillaServer\\world"
'C:\\\\Users\\\\joaop\\\\Desktop\\\\VanillaServer\\\\world'
You only have to escape them when entering the paths directly in your source; if you read those paths from a file, from user input, or from some library function, they will automatically be escaped.


Backslashes are used for escape characters so when the interpreter sees the \ in your file path string it attempts to use them as an escape character (which are things like \n for new line and \t for tabs).
There are 2 ways around this, using raw strings or double slashing your file path so the interpeter ignores the escape sequence. Use a r to specify a raw string or \\. Now the choice in which you use is up to you but personally I prefer raw strings.
#with raw strings
shutil.copy2(r"C:\Users\joaop\Desktop\VanillaServer\world",r"C:\Users\joaop\Desktop\VanillaServer\Backups")
for filename in os.listdir(r"C:\Users\joaop\Desktop\VanillaServer\Backups"):
if filename == world:
os.rename(filename, "Backup " + date)
#with double slashes
shutil.copy2("C:\\Users\\joaop\\Desktop\\VanillaServer\\world","C:\\Users\\joaop\\Desktop\\VanillaServer\\Backups")
for filename in os.listdir("C:\\Users\\joaop\\Desktop\\VanillaServer\\Backups"):
if filename == world:
os.rename(filename, "Backup " + date)

Related

Os.chdir with non-Latin characters

While learning the os module in Python and I've come across a problem.
Let's pretend my current working directory is: C:\Users\Москва\Desktop\Coding\Project 1.
I'd like to change the cwd to Desktop but since the path contains some Russian letters (Москва) it throws a Syntax error:
print(os.getcwd()) # C:\Users\Москва\Desktop\Coding\Project 1
os.chdir('C:\Users\Москва\Desktop')
SyntaxError: (unicode error) 'unicodeescape' codec can't decode bytes...
How shall I usually treat non-standard characters in paths and change the directory in my case?

It isn't about the russian, it's about the backslash with u: \U.
When you print os.getcwd, escaped backslashes goes away:
os.getcwd()
# 'C:\\Users\\chris\\Documents\\Москва\\test'
print(os.getcwd())
C:\Users\chris\Documents\Москва\test
And now if you try to use the printed one by copy-paste, python will understand \Users part as a unicode but of course fail. You can simply reproduce by executing
"\Uaaaa"
SyntaxError: (unicode error) 'unicodeescape' codec can't decode bytes in position 0-1: truncated \UXXXXXXXX escape
You can either use raw string, or use escaped backslashes:
os.chdir(r'C:\Users\sjysk\Documents\Москва')
# ^ note `r` here
os.getcwd()
# 'C:\\Users\\chris\\Documents\\Москва'
os.chdir('C:\\Users\\sjysk\\Documents\\Москва')
os.getcwd()
# 'C:\\Users\\chris\\Documents\\Москва'

Python : Issue is checking os.path.exists

I am trying to check if a particular directory path exists or not.
below is my code
temp_path = '\\diwali\NSID-HYD-01\college'
meta_path = os.path.realpath(temp_path)
print(os.path.exists(meta_path))
When I am trying to execute this, it is throwing error as below
temp_path = '\\diwali\NSID-HYD-01\college'
# ^
error
SyntaxError: (unicode error) 'unicodeescape' codec can't decode bytes in position 8-9: malformed \N character escape
Help me resolve this.

Python interprets backslashes (\) inside strings as leading characters for escape codes. For example \n is a line-feed character.
If you want it to treat them as simply backslashes, add an r before the string, like so:
temp_path = r'\\diwali\NSID-HYD-01\college'

another method is using two backslashes \\ before N like this:
temp_path = '\\diwali\\NSID-HYD-01\college'
If you are get it from UI (as you mentioned in comments) you can replace \ with \\:
temp_path = '\\diwali\NSID-HYD-01\college'.replace("\\", "\\\\")
# '\\diwali\\NSID-HYD-01\\college'

python csv files read and upload

I want to upload all the csv files that meet certain condition in a directory to a database. But I encounter an error at the beginning of my code.
mypath = "D:\user\01367564\Project Coordinator\Database Trying\all data csv"
csv_name_reg = r'^[0-9]{11}_HKG_[0-9]{14}_v2-0.csv$'
The error is below
File "D:\user\01367564\Project Coordinator\Database Trying\Upload_CA_Manifest.py", line 9
mypath = "D:\user\01367564\Project Coordinator\Database Trying\all data csv"
^
SyntaxError: (unicode error) 'unicodeescape' codec can't decode bytes in position 2-3: truncated \uXXXX escape
Can you help me? Thank you.

Currently your path looks like it's meant to contain a Unicode character with the \u.... Please note that on Windows you have three options for paths:
Raw strings
mypath = r"D:\user\01367564\Project Coordinator\Database Trying\all data csv"
Escaped backslashes
mypath = "D:\\user\\01367564\\Project Coordinator\\Database Trying\\all data csv"
Forward slashes
mypath = "D:/user/01367564/Project Coordinator/Database Trying/all data csv"

In Python, there are some cool backslash escapes. A "\" inside a string plus a character(s).
Some notable ones are "\n" and "\t" which are newline and tab. A non-builtin backslash escape will be turned into the actual character in the final string. "\\" will turn into one "\" during, say, a print statement.
The escape Python thinks your using is the unicode escape. "\uXXXX". To fix this all you need is to replace each backslash with a double backslash. "\\". So this string will work: "D:\\user\\01367564\\Project Coordinator\\Database Trying\\all data csv"
For a full list of Python Backslash Escapes look at the Python Docs.

How do I load fiducial node data from Slicer in Python? [duplicate]

This question already has answers here:
How should I write a Windows path in a Python string literal?
(5 answers)
Closed 2 years ago.
The community reviewed whether to reopen this question last year and left it closed:
Original close reason(s) were not resolved
I am using Python 3.1 on a Windows 7 machine. Russian is the default system language, and utf-8 is the default encoding.
Looking at the answer to a previous question, I have attempting using the "codecs" module to give me a little luck. Here's a few examples:
>>> g = codecs.open("C:\Users\Eric\Desktop\beeline.txt", "r", encoding="utf-8")
SyntaxError: (unicode error) 'unicodeescape' codec can't decode bytes in position 2-4: truncated \UXXXXXXXX escape (<pyshell#39>, line 1)
>>> g = codecs.open("C:\Users\Eric\Desktop\Site.txt", "r", encoding="utf-8")
SyntaxError: (unicode error) 'unicodeescape' codec can't decode bytes in position 2-4: truncated \UXXXXXXXX escape (<pyshell#40>, line 1)
>>> g = codecs.open("C:\Python31\Notes.txt", "r", encoding="utf-8")
SyntaxError: (unicode error) 'unicodeescape' codec can't decode bytes in position 11-12: malformed \N character escape (<pyshell#41>, line 1)
>>> g = codecs.open("C:\Users\Eric\Desktop\Site.txt", "r", encoding="utf-8")
SyntaxError: (unicode error) 'unicodeescape' codec can't decode bytes in position 2-4: truncated \UXXXXXXXX escape (<pyshell#44>, line 1)
My last idea was, I thought it might have been the fact that Windows "translates" a few folders, such as the "users" folder, into Russian (though typing "users" is still the correct path), so I tried it in the Python31 folder. Still, no luck. Any ideas?

The problem is with the string
"C:\Users\Eric\Desktop\beeline.txt"
Here, \U in "C:\Users... starts an eight-character Unicode escape, such as \U00014321. In your code, the escape is followed by the character 's', which is invalid.
You either need to duplicate all backslashes:
"C:\\Users\\Eric\\Desktop\\beeline.txt"
Or prefix the string with r (to produce a raw string):
r"C:\Users\Eric\Desktop\beeline.txt"

Typical error on Windows because the default user directory is C:\user\<your_user>, so when you want to pass this path as a string argument into a Python function, you get a Unicode error, just because the \u is a Unicode escape. If the next 8 characters after the \u are not numeric this produces an error.
To solve it, just double the backslashes: C:\\user\\<\your_user>...
This will ensure that Python treats the single backslashes as single backslashes.

Prefixing with 'r' works very well, but it needs to be in the correct syntax. For example:
passwordFile = open(r'''C:\Users\Bob\SecretPasswordFile.txt''')
No need for \\ here - maintains readability and works well.

With Python 3 I had this problem:
self.path = 'T:\PythonScripts\Projects\Utilities'
produced this error:
self.path = 'T:\PythonScripts\Projects\Utilities'
^
SyntaxError: (unicode error) 'unicodeescape' codec can't decode bytes in
position 25-26: truncated \UXXXXXXXX escape
the fix that worked is:
self.path = r'T:\PythonScripts\Projects\Utilities'
It seems the '\U' was producing an error and the 'r' preceding the string turns off the eight-character Unicode escape (for a raw string) which was failing. (This is a bit of an over-simplification, but it works if you don't care about unicode)
Hope this helps someone

Or you could replace '\' with '/' in the path.

path = pd.read_csv(**'C:\Users\mravi\Desktop\filename'**)
The error is because of the path that is mentioned
Add 'r' before the path
path = pd.read_csv(**r'C:\Users\mravi\Desktop\filename'**)
This would work fine.

I had this same error in python 3.2.
I have script for email sending and:
csv.reader(open('work_dir\uslugi1.csv', newline='', encoding='utf-8'))
when I remove first char in file uslugi1.csv works fine.

Refer to openpyxl document, you can do changes as followings.
from openpyxl import Workbook
from openpyxl.drawing.image import Image
wb = Workbook()
ws = wb.active
ws['A1'] = 'Insert a xxx.PNG'
# Reload an image
img = Image(**r**'x:\xxx\xxx\xxx.png')
# Insert to worksheet and anchor next to cells
ws.add_image(img, 'A2')
wb.save(**r**'x:\xxx\xxx.xlsx')

I had same error, just uninstalled and installed again the numpy package, that worked!

I had this error.
I have a main python script which calls in functions from another, 2nd, python script.
At the end of the first script I had a comment block designated with ''' '''.
I was getting this error because of this commenting code block.
I repeated the error multiple times once I found it to ensure this was the error, & it was.
I am still unsure why.

Python - Must add r when opening a file

I have several .py files and I can open my file everywhere, except in my test.py file (I test scripts and functions there) instead of this:
file = open("C:\Users\User\Desktop\key_values.txt", "r")
I need to use this (with r) to avoid error:
file = open(r"C:\Users\User\Desktop\key_values.txt", "r")
I get this error: (when I try to open a file without r in my test.py script)
SyntaxError: (unicode error) 'unicodeescape' codec can't decode bytes in position 2-3: truncated \UXXXXXXXX escape
Any idea why is this happening ?

Backslash is an escape character, so you can include characters like "\n" (new line) and "\t" (tab). The r before the string means means "my backslashes are not escape characters".
Interestingly, it looks like your string "C:\Users\User\Desktop\key_values.txt" works ok in python 2 because none of the backslashes are part of anything looking like a known escape sequence. But in python 3, "\Uxxxx" indicates a unicode character. So maybe that is why some of your python files can cope and some can't.

The other answers are OK.. but this a time saving trick:
Try using slashes instead of backslashes:
file = open("C:/Users/User/Desktop/key_values.txt", "r")
It works in Windows. Tried with Python 2.7
Hope this helps

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