将列表输出为文本文件

Question

I was trying to improve my friend's Python 'Twitch account checker' (basically gets a list of usernames from a text file and checks if they're available or taken on Twitch.tv). I was going to improve it in a way that it would output the available usernames into a text file (in the same location as the original list). I was actually searching Stack Overflow and found a post which 'explained' how to actually output a list (I put the available usernames into a separate list) into a text file.

When running the script, it works fine up to the part where it's supposed to save the available usernames. Then, I get the following error:

Traceback (most recent call last):
  File "multithreadtwitchchecker.py", line 44, in <module>
    output_available_usernames('availableusernames.txt')
  File "multithreadtwitchchecker.py", line 37, in output_available_usernames
    AVAILABLE_USERNAMES = f.write(AVAILABLE_USERNAMES.split('\n'))
AttributeError: 'list' object has no attribute 'split'

Here's the code:

from multiprocessing.pool import ThreadPool
import re
import requests
import sys

try:
    input = raw_input
except NameError:
    pass

TWITCH_URL = "https://www.twitch.tv/{username}"
TWITCH_REGEX = re.compile(r"^[a-zA-Z0-9_]{4,25}$")
MAX_THREADS = 25
MESSAGES = {True: "Available", False: "Taken"}
AVAILABLE_USERNAMES = []

def read_valid_usernames(filename):
    """Reads a list of usernames and filters out invalid ones."""
    try:
        with open(filename, "r") as fin:
            return [username for username in map(str.strip, fin) if TWITCH_REGEX.match(username)]
    except IOError:
        sys.exit("[!] '{}' - Invalid File".format(filename))

def username_available(username):
    """Checks if a 404 response code is given when requesting the profile. If it is, it is presumed to be available"""
    try:
        return username, requests.get(TWITCH_URL.format(username=username)).status_code == 404
        AVAILABLE_USERNAMES.append(username)
    except Exception as e:
        print(e)

def output_available_usernames(filename):
    """Gets a filename to output to and outputs all the valid usernames to it"""
    global AVAILABLE_USERNAMES
    f = open(filename, 'w')
    AVAILABLE_USERNAMES = f.write(AVAILABLE_USERNAMES.split('\n'))

usernames = read_valid_usernames(input("Enter path to list of usernames: "))

for username, available in ThreadPool(MAX_THREADS).imap_unordered(username_available, usernames):
    print("{:<{size}}{}".format(username, MESSAGES.get(available, "Unknown"), size=len(max(usernames, key=len)) + 1)) 

output_available_usernames('availableusernames.txt')

Answer 1

Well, writing to a file can be done like this:

def output_available_usernames(filename):
    global AVAILABLE_USERNAMES
    with open(filename, 'w') as f:
        for name in AVAILABLE_USERNAMES:
            f.write(name + '\n')

As jonrsharpe said, split is going in the wrong direction.

However, your code has a deeper problem right now. You append to AVAILABLE_USERNAMES after the return statement, so that code never executes, and AVAILABLE_USERNAMES will always be empty. You instead want something like this:

def username_available(username):
    """Checks if a 404 response code is given when requesting the profile. If it is, it is presumed to be available"""
    try:
        if requests.get(TWITCH_URL.format(username=username)).status_code == 404:
            AVAILABLE_USERNAMES.append(username)
            return username, True
        else:
            return username, False
    except Exception as e:
        print(e)