I have to take a large list of words in the form:
['this\n', 'is\n', 'a\n', 'list\n', 'of\n', 'words\n']
and then using the strip function, turn it into:
['this', 'is', 'a', 'list', 'of', 'words']
I thought that what I had written would work, but I keep getting an error saying:
"'list' object has no attribute 'strip'"
Here is the code that I tried:
strip_list = []
for lengths in range(1,20):
strip_list.append(0) #longest word in the text file is 20 characters long
for a in lines:
strip_list.append(lines[a].strip())
All other answers, and mainly about list comprehension, are great. But just to explain your error:
strip_list = []
for lengths in range(1,20):
strip_list.append(0) #longest word in the text file is 20 characters long
for a in lines:
strip_list.append(lines[a].strip())
a
is a member of your list, not an index. What you could write is this:
[...]
for a in lines:
strip_list.append(a.strip())
Another important comment: you can create an empty list this way:
strip_list = [0] * 20
But this is not so useful, as .append
appends stuff to your list. In your case, it's not useful to create a list with defaut values, as you'll build it item per item when appending stripped strings.
So your code should be like:
strip_list = []
for a in lines:
strip_list.append(a.strip())
But, for sure, the best one is this one, as this is exactly the same thing:
stripped = [line.strip() for line in lines]
In case you have something more complicated than just a .strip
, put this in a function, and do the same. That's the most readable way to work with lists.
list comprehension?
[x.strip() for x in lst]
my_list = ['this\n', 'is\n', 'a\n', 'list\n', 'of\n', 'words\n']
print([l.strip() for l in my_list])
Output:
['this', 'is', 'a', 'list', 'of', 'words']
You can use lists comprehensions:
strip_list = [item.strip() for item in lines]
Or the map
function:
# with a lambda
strip_list = map(lambda it: it.strip(), lines)
# without a lambda
strip_list = map(str.strip, lines)
This can be done using list comprehensions as defined in PEP 202
[w.strip() for w in ['this\n', 'is\n', 'a\n', 'list\n', 'of\n', 'words\n']]
If you need to remove just trailing whitespace, you could use str.rstrip()
, which should be slightly more efficient than str.strip()
:
>>> lst = ['this\n', 'is\n', 'a\n', 'list\n', 'of\n', 'words\n']
>>> [x.rstrip() for x in lst]
['this', 'is', 'a', 'list', 'of', 'words']
>>> list(map(str.rstrip, lst))
['this', 'is', 'a', 'list', 'of', 'words']
Source: Stackoverflow.com