问题
cat_sums[cat] += value
TypeError: 'int' object is not iterable
My input is this:
defaultdict(<type 'list'>, {'composed': [0], 'elated': [0], 'unsure': [0], 'hostile': [0], 'tired': [0], 'depressed': [0], 'guilty': [0], 'confused': [0], 'clearheaded': [0], 'anxious': [0], 'confident': [0], 'agreeable': [0], 'energetic': [0]})
And this is assigned to something called catnums
accumulate_by_category(worddict, catnums, categories)
def accumulate_by_category(word_values, cat_sums, cats):
for word, value in word_values.items():
for cat in cats[word]:
cat_sums[cat] += value
Now as far as I can tell, I'm not trying to iterate over an integer. I'm trying to add a value to another value inside catnums.
Is it possible that it is having trouble with the "cats" argument inside my accumulate_by_category() function?
回答1:
Each of your values is a list. The +
operator, when applied to lists adds an iterable to a list. It doesn't append a single value:
>>> [1,2] + [3,4]
[1, 2, 3, 4]
>>> [1,2] + 3
TypeError: can only concatenate list (not "int") to list
It looks like you want to do cat_sums[cat].append(value)
.
回答2:
+
, when applied to lists, is concatenation. As BrenBarn said, [1, 2] + [3, 4] == [1, 2, 3, 4]
.
But if you are actually trying to add numbers, as implied by your statement "I'm trying to add a value to another value inside catnums," then append
will not do what you want.
If this is the case then the dictionary you show is probably incorrect. It's not a mapping of words to numbers; it's a mapping of words to lists of numbers (namely the list [0]
). If you're trying to maintain a count of words, this is not what you want; you want {'composed': 0, 'elated': 0, ...}
(note the lack of square brackets). Then the +=
statement will work as expected.
If you cannot change the dictionary but simply want to change the number in the list, you can say cat_sums[cat][0] += value
. However, it would make far more sense (if this is what you're after) to simply convert the "lists of zero" into plain old zeroes.
回答3:
If anyone is getting this error inside a Django template …
When you do:
{% for c in cat_sums.keys %}
then, behind the scenes, the Django template language first tries a cat_sums['keys']
lookup. Normally this would fail and Django would next look for a method. But since this is a defaultdict
, the default value gets stored instead.
If the dict was created with
cat_sums = defaultdict(int)
What gets executed is:
for c in cat_sums['keys']:
i.e.,
for c in 0:
which quite rightly throws an error as the value 0
is not iterable.
Resolution? Pass dict(cat_sums)
inside the context so the view gets a regular dict
.
来源:https://stackoverflow.com/questions/11533650/getting-int-object-is-not-iterable