AttributeError dict object has no attribute predictors

Question

I am new to python and couldn t find the answer to this  Referring to the code at the end of the message  can I know what does the part  for item  total in totals items    in the line below mean   rankings     total simSums item   item  for item  total in totals items      Also  the code failed and said     AttributeError   dict  object has no attribute  predictors    when I changed all instances of  item s   in the code to  predictor s    Why is that so     Return the Pearson correlation coefficient for p1 and p2 def sim person prefs  p1  p2         Get the list of shared items     si        for item in prefs p1           if item in prefs p2  si item  1        Find the number of elements      n len si         if they have no ratings in common  return 0     if n  0  return 0        Add up all the preferences     sum1   sum  prefs p1  it  for it in si       sum2   sum  prefs p2  it  for it in si          Sum up the squares     sum1Sq   sum  pow prefs p1  it  2  for it in si       sum2Sq   sum  pow prefs p2  it  2  for it in si          Sum up the products     pSum   sum  prefs p1  it  prefs p2  it  for it in si          Calculate Person score     num   pSum -  sum1 sum2 n      den   sqrt  sum1Sq - pow sum1 2  n   sum2Sq - pow sum2 2  n       if den    0  return 0      r   num den     return r    Returns the best matches for person from the prefs dictionary    Number of results and similarity function are optional params  def topMatch prefs  person  n 5  similarity sim person       scores     similarity prefs  person  other   other                 for other in prefs if other  person         Sort the list so the highest scores appear at the top     scores sort       scores reverse       return scores 0 n     Gets recommendations for a person by using a weighted average   of every other user s rankings  def getRecommendations prefs  person  similarity sim person       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 of lower         if sim lt  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

User · Accepted Answer

The dict items iterates over the key-value pairs of a dictionary  Therefore for key  value in dictionary items   will loop over each pair  This is documented information and you can check it out in the official web page  or even easier  open a python console and type help dict items   And now  just as an example    gt  gt  gt  d     hello   34   world   2999   gt  gt  gt  for key  value in d items          print key  value     world 2999 hello 34   The AttributeError is an exception thrown when an object does not have the attribute you tried to access  The class dict does not have any predictors attribute  now you know where to check it       and therefore it complains when you try to access it  As easy as that

User · Answer

Try without dot notation sample dict     name    John    age   29  print sample dict  name      John print sample dict  age      29

[python] AttributeError: 'dict' object has no attribute 'predictors'

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