Split line into category and text

Question

I have list that looks like this:

foo = ["neg * , This is a sentence","pos * , This is another sentence"]

I need to split the sentences in such a way that one value will become the category, neg or pos , and one the sentence. I tried:

for text in foo:
    text = text.split("*")
    for a,b in text:
        cat=a
        text=b

However I get a "too many values to unpack", anyone have an idea?

Answer 1

Your problem is your loop is horribly constructed (which is excusable, since you are obviously new to the whole thing)

Try this safer method (a list-comprehension):

>>> foo = ["neg * , This is a sentence","pos * , This is another sentence"]
>>> [p.split('*', 1) for p in foo]
[['neg ', ' , This is a sentence'], ['pos ', ' , This is another sentence']]

Now you have a list of [CAT, TEXT] items.

>>> l = [p.split('*', 1) for p in foo]
>>> for cat, text in l:
    print 'cat: %s, text: %s' % (cat, text)

cat: neg , text:  , This is a sentence
cat: pos , text:  , This is another sentence

Answer 2

The line for a,b in text: isn't appropriate. A better choice is a,b=text . The former code operates on a list of pairs, the latter operates on a single pair.

Applying that advice, and removing redundancies:

foo = ["neg * , This is a sentence","pos * , This is another sentence"]
for text in foo:
    a,b = text.split("*")
    # Now do something with 'a' and 'b'

If you really want to re-use the text variable, this works:

for text in foo:
    a, text = text.split("*")
    # Now do something with 'a' and 'text'

Answer 3

You're doing the assignment part in the inner loop wrong. Here, try this

lines = ["neg * , This is a sentence","pos * , This is another sentence"]
for line in lines:
    category, sentence = line.split("*", 1)

Answer 4

You're iterating over strings in the second loop

for text in foo:
    text = text.split("*")
    a,b = text:

In that case, you assign a to the first element of text and b the second one. Otherwise you're splitting the string into characters and you don't have the same number of variables as the number of characters

Answer 5

textList = []
catList = []
for str in foo:
    (cat,text) = str.split('*')
    textList.append(text)
    catList.append(cat)

Then textList is a list of text strings and catList is a list of cat strings. Otherwise you won't be able to access all the different cats and texts.