Question

I am having problems writing to a file where I am using pylast. Following a template given in pylast, I added a regular expression to extract what I need (which is doing ok), but when I tried to print to a file, I get an error, and don’t know how to fix it (I am teaching myself python and some of its libraries).
I suspect there is an encoding specification I need to make somewhere (some of the output to screen also shows non-standard characters). I don’t know how to solve my problem.
Can anybody help?
Thanks

import re
import pylast

RawArtistList = []
ArtistList = []

# You have to have your own unique two values for API_KEY and API_SECRET
# Obtain yours from http://www.last.fm/api/account for Last.fm
API_KEY = "XXX"
API_SECRET = "YYY"

###### In order to perform a write operation you need to authenticate yourself
username = "username"
password_hash = pylast.md5("password")
network = pylast.LastFMNetwork(api_key = API_KEY, api_secret = API_SECRET, username = username, password_hash = password_hash)





##          _________INIT__________
COUNTRY = "Germany"

#---------------------- Get Geo Country --------------------
geo_country = network.get_country(COUNTRY)

#----------------------  Get artist --------------------
top_artists_of_country = str(geo_country.get_top_artists())

RawArtistList = re.findall(r"u'(.*?)'", top_artists_of_country)

top_artists_file = open("C:\artist.txt", "w")
for artist in RawArtistList:
  print artist
  top_artists_file.write(artist + "\n")

top_artists_file.close()

The name of the file I am trying to create “artist.txt” changes to “x07rtist.txt” and the error kicks in. I get this:

Traceback (most recent call last):
File "C:\music4A.py", line 32, in <module>
top_artists_file = open("C:\artist.txt", "w")
IOError: [Errno 22] invalid mode ('w') or filename:'C:\x07rtist.txt'

Thank you very much for any help! Cheers.

Answer 1

The Python docs say:

The backslash () character is used to escape characters that
otherwise have a special meaning, such as newline, backslash itself,
or the quote character.

…so when you say

top_artists_file = open("C:\artist.txt", "w")

that string literal is being interpreted as

C:  \a rtist.txt

…where \a is a single character that has a value of 0x07.

…that line should instead be:

# doubling the backslash prevents misinterpreting the 'a'
top_artists_file = open("C:\\artist.txt", "w")

or

# define the string literal as a raw string to prevent the escape behavior
top_artists_file = open(r"C:\artist.txt", "w")

or

# forward slashes work just fine as path separators on Windows.
top_artists_file = open("C:/artist.txt", "w")