python - Calculating weighted average from a list -

this 1 list

[74.0, 96.0, 72.0, 88.0, ['71', '80', '83', '77', '90', '88', '95', '71', '76', '94'], 80.0, 74.0, 98.0, 77.0] 

74 calculated weight .1, 96 weight .1, 72 weight .15, 88 weight .05, average of (71,80,83,77,90,88,95,71,76,94) calculated weight .3, 80 calculated weight .08, 74 weight .08, 98 .09 , lastly 77 .05. each score should multiplied appropriate weight.

here function

def weighted_total_score(student_scores):     return((int(student_scores[0])*.1)+(int(student_scores[1])*.1)+(int(student_scores[2])*.15)+(int(student_scores[3])*.05)+(int(student_scores[4][0])*.3)+(int(student_scores[5])*.08)+(int(student_scores[5])*.08)+(int(student_scores[5])*.09)+(int(student_scores[8])*.05)) 

the expected value should 82.94 getting 78.48

you slicing outer list:

student_scores[4:5][0] 

slicing produces new list, in case 1 element, [0] selects that nested list:

>>> student_scores = [74.0, 96.0, 72.0, 88.0, ['71', '80', '83', '77', '90', '88', '95', '71', '76', '94'], 80.0, 74.0, 98.0, 77.0] >>> student_scores[4:5] [['71', '80', '83', '77', '90', '88', '95', '71', '76', '94']] >>> student_scores[4:5][0] ['71', '80', '83', '77', '90', '88', '95', '71', '76', '94'] 

perhaps want use student_scores[4][0] (no slicing, 4th element) instead? that'd produce '71':

>>> student_scores[4][0] '71' 

you skipping student_scores[5], , indexerror student_scores[9], doesn't exist.

you want avoid typing direct references; specify weights sequence , use zip() generator expression , sum() calculate weighted sum:

def weighted_total_score(student_scores):     weights = .1, .1, .15, .05, .3, .08, .08, .09, .05                      return sum(int(s[0] if isinstance(s, list) else s) * w                s, w in zip(student_scores, weights)) 

this uses isinstance(s, list) detect 1 list object , extract first value that.

if need average of the nested list, calculate on spot:

def average(string_scores):     return sum(map(int, string_scores), 0.0) / len(string_scores)  def weighted_total_score(student_scores):     weights = .1, .1, .15, .05, .3, .08, .08, .09, .05                      return sum(int(average(s[0]) if isinstance(s, list) else s) * w                s, w in zip(student_scores, weights)) 

the average() function here converts each string in list integer, sums integers , divides result length of list. sum() started floating point 0.0 force total float, makes sure division producing float, matters on python 2.