Am I able to slice a list of strings? If it is possible could anyone please tell me how to do it so that I am able to print out a particular string instead of the five that make up the list. Cheers.
eg.
mylist = ['apples' 'oranges' 'lemons' 'cucumbers' 'bananas']
print 'orange'
** The programming language i am using is python. Every time I code it mylist[2] it comes out as an error. The list I am using is extracting the strings from a html rss feed. Each string is a new news heading. However, even when it updates constantly there are always 5 strings in the list and it tells me list index out of range. But if I just print the entire list it works fine**
#URLS for RSS Feeds
url_national = 'http://feeds.news.com.au/public/rss/2.0/news_national_3354.xml'
url_sport = 'http://feeds.news.com.au/public/rss/2.0/news_sport_3168.xml'
url_world = 'http://feeds.news.com.au/public/rss/2.0/news_theworld_3356.xml'
url_technology = 'http://feeds.news.com.au/public/rss/2.0/news_tech_506.xml'
def headlines (url):
web_page = urlopen(url)
html_code = web_page.read()
web_page.close()
return findall(r'<item><title>([^<]*)</title>', html_code)
#headlines list
list_national = [headlines(url_national)]
list_sport = [headlines(url_sport)]
list_world = [headlines(url_world)]
list_technology = [headlines(url_technology)]
def change_category():
if label_colour.get() == 'n':
changeable_label['text'] = list_national #here I would slice it but it doesn't work
elif label_colour.get() == 's':
changeable_label['text'] = list_sport
elif label_colour.get() =='w':
changeable_label['text'] = list_world
else:
changeable_label['text'] = list_technology
the reason I need to slice it into individual heading is so when the radio button is pressed for my GUI it prints them in a numbered list on the label not all just running on one line next to them - sorry i hope that makes sense
What language are you using here? Usually you can use an index to access a particular entry in a list. For example:
print myList[1]
Commas are missing in your list creation. You have to do it like this:
mylist = ['apples', 'oranges', 'lemons', 'cucumbers', 'bananas']
And you will be able to work with your list
mylist[0] # 'apples'
mylist[-1] # 'bananas'
mylist[2] # 'lemons'
I think the error you are getting is something like this:
mylist = ['apples' 'oranges' 'lemons' 'cucumbers' 'bananas']
print mylist[5]
IndexError: list index out of range
The reason is the elements in a list are indexed from 0
not 1
. The mylist
has 5
elements starting from 0
to 4
. So when you call print mylist[5]
it will definitely give an error as there is no 6th
element in the list.
Here is the official doc regarding list please have a look. I hope it was helpful!
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