[英]sys.argv list index out of range error
I am trying to run this script that grabs rss feeds on the environment "Thonny" but I just keep receiving this error of "IndexError: List index out of range" 我正在尝试运行在“ Thonny”环境中获取rss feed的脚本,但是我一直收到以下错误:“ IndexError:列表索引超出范围”
Traceback (most recent call last):
File "C:\Users\uri\rssfeedfour.py", line 11, in <module>
url = sys.argv[1]
IndexError: list index out of range
How do I resolve this to keep from getting this error over and over again. 我如何解决此问题,以免一遍又一遍地出现此错误。 Im not sure how to solve this as I am a beginner.
我不知道该如何解决这个问题,因为我是新手。 Do I need to define it, if so how?
我是否需要定义它(如果这样)? or could I take it out and go a different direction?
还是我可以将其取出并朝另一个方向走? Here is the code.
这是代码。
import feedparser
import time
from subprocess import check_output
import sys
#feed_name = 'TRIBUNE'
#url = 'http://chicagotribune.feedsportal.com/c/34253/f/622872/index.rss'
feed_name = sys.argv[1]
url = sys.argv[2]
db = 'http://feeds.feedburner.com/TheHackersNews'
limit = 12 * 3600 * 1000
current_time_millis = lambda: int(round(time.time() * 1000))
current_timestamp = current_time_millis()
def post_is_in_db(title):
with open(db, 'r') as database:
for line in database:
if title in line:
return True
return False
def post_is_in_db_with_old_timestamp(title):
with open(db, 'r') as database:
for line in database:
if title in line:
ts_as_string = line.split('|', 1)[1]
ts = long(ts_as_string)
if current_timestamp - ts > limit:
return True
return False
#
# get the feed data from the url
#
feed = feedparser.parse(url)
#
# figure out which posts to print
#
posts_to_print = []
posts_to_skip = []
for post in feed.entries:
# if post is already in the database, skip it
# TODO check the time
title = post.title
if post_is_in_db_with_old_timestamp(title):
posts_to_skip.append(title)
else:
posts_to_print.append(title)
#
# add all the posts we're going to print to the database with the current timestamp
# (but only if they're not already in there)
#
f = open(db, 'a')
for title in posts_to_print:
if not post_is_in_db(title):
f.write(title + "|" + str(current_timestamp) + "\n")
f.close
#
# output all of the new posts
#
count = 1
blockcount = 1
for title in posts_to_print:
if count % 5 == 1:
print("\n" + time.strftime("%a, %b %d %I:%M %p") + ' ((( ' + feed_name + ' - ' + str(blockcount) + ' )))')
print("-----------------------------------------\n")
blockcount += 1
print(title + "\n")
count += 1
sys.argv
is a list in Python, which contains the command-line arguments passed to the script. sys.argv
是Python中的列表,其中包含传递给脚本的命令行参数。 sys.argv[0]
contains the name of the script, sys.argv[1]
contains the first argument and so on. sys.argv[0]
包含脚本的名称, sys.argv[1]
包含第一个参数,依此类推。
To prevent this error, you need to give command line arguments when starting the script. 为防止此错误,启动脚本时需要提供命令行参数。 For example, you can start this script without any errors by
例如,您可以通过以下方式启动此脚本,而不会出现任何错误:
python rssfeedfour.py TRIBUNE http://chicagotribune.feedsportal.com/c/34253/f/622872/index.rss
You can also modify the script so that it works using the default arguments if you don't provide any command line arguments. 您也可以修改脚本,以便在不提供任何命令行参数的情况下使用默认参数来工作。
try:
feed_name = sys.argv[1]
except IndexError:
feed_name = 'TRIBUNE'
try:
url = sys.argv[2]
except IndexError:
url = 'http://chicagotribune.feedsportal.com/c/34253/f/622872/index.rss'
You can learn more about handling errors here . 您可以在此处了解有关处理错误的更多信息。
Although it is much more convenient to use argparse library. 尽管使用argparse库要方便得多。
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