Hi again, Tutor List.
I am trying to figure out a problem I've run into. Let me first say
that this is an assignment, so please don't give me any answers, but
just nudge me in the general direction. So the task is this: from a
text file, populate three different dictionaries with various
information. The text file is structured like so:
Georgie Porgie
87%
$$$
Canadian, Pub Food
So name, rating, price range, and food offered. After food offered
follows a blank line before the next restaurant is listed.
The three dictionaries are:
name_to_rating = {}
price_to_names = {'$': [], '$$': [], '$$$': [], '$$$$': []}
cuisine_to_names = {}
Now I've poked at this for a while now, and one idea I had, which I
worked on for quite a while, was that since the restaurants all start
at index 0, 5, 10 and so on, I could structure a while loop like this:
with open('textfile.txt') as mdf:
file_length = len(mdf.readlines())-1
mdf.seek(0)
data = mdf.readlines()
i = 0
while file_length > 0:
name_to_rating[data[i]] = int(data[i+1][:2])
price_to_names[data[i+2].strip()].append(data[i].strip())
# here's the cuisine_to_names part
i += 5
file_length -= 5
And while this works, for the two first dictionaries, it seems really
cumbersome -- especially that second expression -- and very, very
brittle. However, even if I was happy with that, I can't figure out
what to do in the situation where:
data[i+3] = 'Canadian, Pub Food' #should be two items, is currently a string.
My problem is that I'm... stupid. I can split the entry into a list
with two items, but even so I don't know how to add the key: value
pair to the dictionary so that the value is a list, which I then later
can append things to.
I'm sorry, this sounds terribly confused, I know. I had another idea
to feed each line to a function, because no restaurant name has a
comma in it, and food offered always has a comma in it if the
restaurant offers more than one kind. But again, this seems really
brittle.
I guess we can't use objects (for some reason), but that doesn't
really matter because if I can't extract the data into dictionaries I
wouldn't have much use of an object either way. So yeah, my two
questions are these:
is there a better way to move through the text file other than a
really convoluted expression? And how do I add more than one value to
a key in a dictionary, if the values are added at different times and
there's no list created in the dictionary to begin with?
(I briefly though about initializing empty lists for each food type in
the dictionary and go with my horrible expressions, but that seems
like a cheap way out of a problem I'd rather tackle in a good way to
begin with)
Much thanks in advance.
--
best regards,
Robert S.
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