將字典值附加到python中的列表

Question

我在將與鍵“ id”一致的學生詞典值附加到列表時遇到麻煩。 任何幫助深表感謝！

students = list();
students.append( {'id':12345, 'first_name':'Alice', 
'last_name':'Anderson','assignments':[('assignment_1',0),('assignment_2',2), 
('assignment_3',3)]})
students.append({'id':22345, 'first_name':'John', 
'last_name':'Sparks','assignments':[('assignment_1',2),('assignment_2',3), 
('assignment_3',4)]})
students.append({'id':32345, 'first_name':'Taylor', 
'last_name':'Mason','assignments':[('assignment_1',3),('assignment_2',2), 
('assignment_3',3)]})

def return_passing(students):    
    grade_sum = 0
    counter = 0
    for s in students:  #loop thru students
        for assignment, grade in s['assignments']: 
            grade_sum += grade
            counter += 1
            average = grade_sum / counter
            lst = list()
        if average >= 2.0:
        lst.append((s['id']))
        return lst

return_passing(students) 

print(return_passing(students))   

Answer 1

在錯誤的地方初始化事物會遇到一些問題，因此它們會被重置。 注釋中有這些說明：

def return_passing(students):    
    lst = [] # initialize lst here
    for s in students:  #loop thru students
        grade_sum = 0 # reset these for each student
        counter = 0
        for assignment, grade in s['assignments']: 
            grade_sum += grade
            counter += 1
        # now that we have gone throug all assignments
        # compute average
        average = float(grade_sum) / counter # convert to float for precision
        if average >= 2.0:
            lst.append(s['id'])
    return lst # return only after you've gone through all students