Question

按值对字典列表进行排序我一直在尝试使用lambda，但我无法弄清楚。

scale = {'A+': 4.3, 'A': 4.0, 'A-': 3.7,
   'B+': 3.3, 'B': 3.0, 'B-': 2.7,
   'C+': 2.3, 'C': 2.0, 'C-': 1.7,
   'D+': 1.3, 'D': 1.0, 'D-': 0.7,
   'F' : 0.0}

subject = {'math':  {('Tom', 'B'), ('Kevin','D')},
   'History':  {('Kate', 'A+'),('Eric','C'),('Hannah','F')}, 
   'English':  {('Eli', 'B-')}}`
from collections import defaultdict
mingrade = 1.7
def pass(subject, mingrade):
    output = defaultdict(list)
    for subject_name,subject_grade in subject.items():
        for student,grade in subject_grade:
        if scale[grade]>=mingrade:
            output[subject_name]+=[student]
return output

我得到了类似的输出 {'math'：['Tom']，'History'：{（'Kate'），（'Eric'）}，'English'：{（'Eli'）} 但我想按名称和等级进行排序 'History'：{（'Kate'），（'Eric'）将变成'History'：{（'Eric'），（'Kate'）}按字母顺序排列。我想按年级获得另一个。成绩较高的学生排名第一。

Answer 1

好吧，为了获得两种不同类型的两种不同输出，我接受了您的代码，然后为函数创建了两种输出，其中一种按字母顺序排序，另一种按等级排序。

scale = {'A+': 4.3, 'A': 4.0, 'A-': 3.7,
   'B+': 3.3, 'B': 3.0, 'B-': 2.7,
   'C+': 2.3, 'C': 2.0, 'C-': 1.7,
   'D+': 1.3, 'D': 1.0, 'D-': 0.7,
   'F' : 0.0}

subject = {'math':  {('Tom', 'B'), ('Kevin','D')},
   'History':  {('Kate', 'A+'),('Eric','C'),('Hannah','F')}, 
   'English':  {('Eli', 'B-')}}
from collections import defaultdict
mingrade = 1.7
def test(subject, mingrade):
    alpha_sort = defaultdict(list)
    grade_sort = defaultdict(list)
    for subject_name,subject_grade in subject.items():
        #here i sort the sets first alphabetically and then by grade
        #the sorted function allows me to pass a function on which i want
        #to sort them as with the key keyword
        sort_alpha = sorted(subject_grade, key=lambda x: x[0].lower())
        sort_grade = sorted(subject_grade, key=lambda x: scale[x[1]], reverse=True)
        #now I loop over each sorted list as you did and store them in a 
        #seperate default dicts
        for student,grade in sort_grade:
            if scale[grade]>=mingrade:
                grade_sort[subject_name]+=[student]
        for student,grade in sort_alpha:
            if scale[grade]>=mingrade:
                alpha_sort[subject_name]+=[student]

    return alpha_sort, grade_sort
alpha, grade = test(subject, mingrade)
print(alpha, grade)

给出此输出

defaultdict(<class 'list'>, {'math': ['Tom'], 'History': ['Eric', 'Kate'], 
'English': ['Eli']}) 
defaultdict(<class 'list'>, {'math': ['Tom'], 'History': ['Kate', 'Eric'], 
'English': ['Eli']})

如何按字典中列表的值排序

1 个答案: