嵌套字典分配错误 - 混淆可变字典

我在嵌套字典中分配困难。我有一个嵌套的词典，有两个学校，三个老师和四个学生。这仅仅是一个玩具的例子，所以我不在乎每个学校的学生和老师都是一样的。但是，我希望每个等级都不同。但是，根据下面的代码，所有班级和所有学校的所有学生的成绩与最后输入的学校/班级相同。嵌套字典分配错误 - 混淆可变字典

schools = ['School A', 'School B'] 
teachers = ['mr. smith', 'ms. jones', 'mr. kronk'] 
students = ['Adam', 'Nick', 'Jeff', 'Dave'] 
grade_dict ={} 
for i in students: 
    grade_dict[i] = '' 
    for j in teachers: 
     teachers_dict[j] = grade_dict 
     for k in schools: 
      school_dict[k] = teachers_dict 
for k in schools: 
    for j in teachers: 
     for i in students: 
      a = [randint(70, 100), randint(70, 100), randint(70, 100)] 
      school_dict[k][j][i] = a

这就是我想要的数据看起来像：

School A mr. smith Adam [71, 72, 82] 
School A mr. smith Nick [86, 80, 96] 
School A mr. smith Jeff [77, 70, 83] 
School A mr. smith Dave [79, 83, 98] 
School A ms. jones Adam [70, 98, 87] 
School A ms. jones Nick [80, 94, 76] 
School A ms. jones Jeff [79, 82, 93] 
School A ms. jones Dave [90, 97, 85] 
School A mr. kronk Adam [93, 75, 95] 
School A mr. kronk Nick [80, 82, 72] 
School A mr. kronk Jeff [75, 72, 89] 
School A mr. kronk Dave [86, 92, 98] 
School B mr. smith Adam [89, 77, 84] 
School B mr. smith Nick [93, 71, 74] 
School B mr. smith Jeff [78, 83, 83] 
School B mr. smith Dave [72, 83, 70] 
School B ms. jones Adam [82, 100, 78] 
School B ms. jones Nick [80, 89, 100] 
School B ms. jones Jeff [91, 81, 77] 
School B ms. jones Dave [86, 86, 74] 
School B mr. kronk Adam [82, 73, 100] 
School B mr. kronk Nick [81, 71, 74] 
School B mr. kronk Jeff [92, 100, 90] 
School B mr. kronk Dave [86, 97, 85]

这不幸的是，相应的字典的样子：

{'School A': {'mr. kronk': {'Adam': [86, 89, 94], 
    'Dave': [74, 85, 86], 
    'Jeff': [79, 94, 70], 
    'Nick': [90, 80, 97]}, 
    'mr. smith': {'Adam': [86, 89, 94], 
    'Dave': [74, 85, 86], 
    'Jeff': [79, 94, 70], 
    'Nick': [90, 80, 97]}, 
    'ms. jones': {'Adam': [86, 89, 94], 
    'Dave': [74, 85, 86], 
    'Jeff': [79, 94, 70], 
    'Nick': [90, 80, 97]}}, 
'School B': {'mr. kronk': {'Adam': [86, 89, 94], 
    'Dave': [74, 85, 86], 
    'Jeff': [79, 94, 70], 
    'Nick': [90, 80, 97]}, 
    'mr. smith': {'Adam': [86, 89, 94], 
    'Dave': [74, 85, 86], 
    'Jeff': [79, 94, 70], 
    'Nick': [90, 80, 97]}, 
    'ms. jones': {'Adam': [86, 89, 94], 
    'Dave': [74, 85, 86], 
    'Jeff': [79, 94, 70], 
    'Nick': [90, 80, 97]}}}

似乎有类似的问题在stackoverflow，但他们不能帮助我解决这里发生的事情。谢谢。

来源

2017-09-18 Geoff Perrin

您可以使用字典解析：

from random import randint 
schools = ['School A', 'School B'] 
teachers = ['mr. smith', 'ms. jones', 'mr. kronk'] 
students = ['Adam', 'Nick', 'Jeff', 'Dave'] 

final_dict = {school:{teacher:{student:[randint(70, 100), randint(70, 100), randint(70, 100)] for student in students} for teacher in teachers} for school in schools}

输出：

{'School A': {'mr. smith': {'Nick': [75, 81, 86], 'Dave': [85, 88, 84], 'Adam': [78, 95, 99], 'Jeff': [74, 95, 81]}, 'ms. jones': {'Nick': [76, 86, 92], 'Dave': [92, 100, 95], 'Adam': [98, 99, 90], 'Jeff': [74, 100, 95]}, 'mr. kronk': {'Nick': [84, 97, 79], 'Dave': [93, 91, 89], 'Adam': [83, 98, 79], 'Jeff': [89, 83, 99]}}, 'School B': {'mr. smith': {'Nick': [70, 78, 89], 'Dave': [81, 95, 92], 'Adam': [95, 100, 91], 'Jeff': [91, 83, 82]}, 'ms. jones': {'Nick': [94, 85, 75], 'Dave': [99, 77, 94], 'Adam': [79, 97, 92], 'Jeff': [91, 84, 79]}, 'mr. kronk': {'Nick': [81, 90, 86], 'Dave': [72, 95, 82], 'Adam': [80, 73, 77], 'Jeff': [88, 88, 95]}}}

来源

2017-09-18 22:28:49 Ajax1234

硬编码像这样最终的字典是不是最好的。 –

这是初始化字典的一种很酷的方式（谢谢！），但并不完全解决在嵌套字典中最低级别创建唯一值的问题。 –

@GeoffPerrin我很抱歉没有意识到你想让学生成绩随机化！请参阅我最近的编辑。 – Ajax1234

你是（重新）在整个字典中使用相同的grade_dict对象。每次迭代创建单独的对象。此外，你并不需要在每个键初始化值：

for i in students: 
    for j in teachers: 
     teachers_dict[j] = {} 
     for k in schools: 
      school_dict[k] = teachers_dict

OTOH，你应该避免使用嵌套collections.defaultdict声明school_dict预分配与值/类型的字典进行。

from collections import defaultdict 

school_dict = defaultdict(lambda: school_dict) # dict nesting is recursive 

for k in schools: 
    for j in teachers: 
     for i in students: 
      school_dict[k][j][i] = [randint(70, 100), randint(70, 100), randint(70, 100)]

来源

2017-09-18 22:19:02

嵌套字典分配错误 - 混淆可变字典

回答

相关问题