Python Namedtuple Indexing Instance

Question

So Here is my code for my lab coding project that I am currently working on:

from collections import namedtuple
Restaurant = namedtuple('Restaurant', 'name cuisine phone dish price')

# Restaurant attributes: name, kind of food served, phone number, best dish, price of that dish

RC = [Restaurant("Thai Dishes", "Thai", "334-4433", "Mee Krob", 12.50), 
      Restaurant("Nobu", "Japanese", "335-4433", "Natto Temaki", 5.50), 
      Restaurant("Nonna", "Italian", "355-4433", "Stracotto", 25.50), 
      Restaurant("Jitlada", "Thai", "324-4433", "Paht Woon Sen", 15.50), 
      Restaurant("Nola", "New Orleans", "336-4433", "Jambalaya", 5.50), 
      Restaurant("Noma", "Modern Danish", "337-4433", "Birch Sap", 35.50), 
      Restaurant("Addis Ababa", "Ethiopian", "337-4453", "Yesiga Tibs", 10.50)]

My question to you as a beginner is: what method(s) should I use to allow my program to index specific parts of the list?

For example, how do I go about indexing a list of all of the restaurants from the greater list? This list includes just the restaurants from the list not all the other information like the phone numbers, etc...

I have used both slice methods and list functions in attempt to figure this out myself and it did not prove to work. >:(

I guess I'm not sure what you mean by index in this circumstance? — Colleen, Mar 28 '13 at 22:03
Assuming you mean the `name` by "all of the restaurants", `RC[0].name` would be the first entry. — Moshe, Mar 28 '13 at 22:05
You already have a list of restaurants. Each restaurant has various bits of data associated with it. Are you asking how to get a list of the *names* of the restaurants? — BrenBarn, Mar 28 '13 at 22:06
"The list of restaurants, arranged alphabetically by restaurant name." — doug_teh_ownerer, Mar 28 '13 at 22:06
Oh, so what you actually need is to SORT based on an attribute. There are plenty of existing answers on that topic — Colleen, Mar 28 '13 at 22:07
http://stackoverflow.com/questions/12087905/pythonic-way-to-sorting-list-of-namedtuples-by-field-name — Colleen, Mar 28 '13 at 22:07
@Colleen I already saw that topic before I posted this. That particular example that was given as a solution did not work for me. — doug_teh_ownerer, Mar 28 '13 at 22:11
Then your question needs to address how it didn't work for you. — Colleen, Mar 28 '13 at 22:12

score 1 · Answer 1 · answered Mar 28 '13 at 22:13

I am not sure when you say index if you just want the values or for performance. But for basic retrieval you could just do something like this

[r.name for r in RC]

Which would give you all the names of restaurants you have in RC

You could get fancier,

RC = [...]
def getValues(name):
   return [getattr(r, name) for r in RC]

Then you can just do,

getValues('name')

If you need it to cache you can look into using memoize

score 0 · Answer 2 · answered Mar 28 '13 at 22:46

Not completely sure what you mean by "index", but this might do what you want:

from collections import namedtuple
Restaurant = namedtuple('Restaurant', 'name cuisine phone dish price')

# Restaurant attributes: name, kind of food served, phone number, best dish, price of that dish

RC = [Restaurant("Thai Dishes", "Thai", "334-4433", "Mee Krob", 12.50),
      Restaurant("Nobu", "Japanese", "335-4433", "Natto Temaki", 5.50),
      Restaurant("Nonna", "Italian", "355-4433", "Stracotto", 25.50),
      Restaurant("Jitlada", "Thai", "324-4433", "Paht Woon Sen", 15.50),
      Restaurant("Nola", "New Orleans", "336-4433", "Jambalaya", 5.50),
      Restaurant("Noma", "Modern Danish", "337-4433", "Birch Sap", 35.50),
      Restaurant("Addis Ababa", "Ethiopian", "337-4453", "Yesiga Tibs", 10.50)]

def retrieve(records, column):
    """ return list of values for column from a list of namedtuples """
    if records and column not in records[0]._fields:
        raise ValueError('invalid column name:' + repr(column))
    return [getattr(rec, column) for rec in records]

print retrieve(RC, 'name')

Output:

['Thai Dishes', 'Nobu', 'Nonna', 'Jitlada', 'Nola', 'Noma', 'Addis Ababa']

Python Namedtuple Indexing Instance

2 Answers2