CODEWITHSUNDEEP
pythoncollective-intelligence
tanaks1789
tanaks1789

Reputation: 1

Python and Collective Intelligence: Chapter 2: Recommending Items

I was learning how Collective Intelligence works and I was practicing doing the example recommendations.py problem in chapter 2. Here is the link:

http://cdn.jampad.net/Library/collectiveintelligence/#calibre_link-201

When I copied and pasted this code:

# Gets recommendations for a person by using a weighted average
# of every other user's rankings
def getRecommendations(prefs,person,similarity=sim_pearson):
  totals={}
  simSums={}
  for other in prefs:
# don't compare me to myself
if other==person: continue
sim=similarity(prefs,person,other)

# ignore scores of zero or lower
if sim<=0: continue
for item in prefs[other]:

  # only score movies I haven't seen yet
  if item not in prefs[person] or prefs[person][item]==0:
    # Similarity * Score
    totals.setdefault(item,0)totals[item]+=prefs[other][item]*sim
    # Sum of similarities
    simSums.setdefault(item,0)
    simSums[item]+=sim

# Create the normalized list
rankings=[(total/simSums[item],item) for item,total in totals.items(  )]

# Return the sorted list
rankings.sort(  )
rankings.reverse(  )
return rankings

Into my recommendations.py file and when I reload the file, I receive a syntax error.

>>> reload(recommendations)
Traceback (most recent call last):
File "<stdin>", line 1, in <module>
File "recommendations.py", line 100
  totals.setdefault(item,0)totals[item]+=prefs[other][item]*sim
                              ^

SyntaxError: invalid syntax

That is the message I received. I'm not sure if I copied and pasted the code properly or if the given line of code is wrong.

Upvotes: 0

Views: 454

Answers (1)

Amber
Amber

Reputation: 526623

This...

totals.setdefault(item,0)totals[item]+=prefs[other][item]*sim

is meant to be two lines:

totals.setdefault(item,0)
totals[item]+=prefs[other][item]*sim

Upvotes: 2

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