创建嵌套列表的问题

Question

我是一个新手，所以如果我忽略了一些基本的东西，请耐心等待，但我正在尝试为我的朋友的瑜伽工作室列出瑜伽课程，该概念上应该看起来像这个：

Monday 

Dynamic Yoga with Mary 6pm 

Soft yoga with Susie 8pm 

Wednesday 

Hatha yoga with Bob 5pm 

Hot yoga with Alice 7pm 

所以我想取得班的名单，然后看看周一是否有瑜伽课。如果有的话，我会在星期一和星期一的所有课程中添加“星期一”，以此类推。

问题：

到目前为止我的代码追加全部那里有瑜伽班的日子，但随后将所有从整周的班每天，当他们应该只添加对应于每个类天。

I.e.当它应该是：

Monday_list = [Monday, [[Class1Monday],[Class2Monday]] 

它来代替：

Monday_list [Monday, [[CLass1Monday],[CLass2Monday],[CLass1Tuesday],[CLass2Tuesday]]] 

这是我的代码（这是对谷歌应用程序引擎，它可以在代码解释一些怪异...）：

def get_classes(): 
    weekly_classes = [] 
    d = {1: 'Monday', 
     2: 'Tuesday', 
     3: 'Wednesday', 
     4: 'Thursday', 
     5: 'Friday', 
     6: 'Saturday', 
     7: 'Sunday'} 
    yoga_classes = Schema.all() #appengine DB request 
    if yoga_classes: 
     #list that will be sent to template 
     for n in range(1,8): 
      day_classes = [] 
      for e in yoga_classes: 
       if e.weekday == n: 
        day = d[n] 
        class_output = [str(e.name), 
            str(e.teacher), 
            str(e.description) 
            ] 
       day_classes.append(class_output) 
      day_output = [day,day_classes] 
      weekly_classes.append(day_output) 
     self.response.out.write(weekly_classes) 

Answer 1

下面是一些pythonic代码，利用itertools。数据按照groupby()的要求排序，然后分组。我发现任何使用范围函数都表示你正在做的事情比Python更C，并且可能有更干净的方法来做到这一点。请注意，绝大多数此代码只是设置虚拟数据来处理。

class Yoga(): 
    def __init__(self,weekday,name,teacher,description): 
     self.weekday=weekday 
     self.name=name 
     self.teacher=teacher 
     self.description=description 
    def __str__(self): 
     return "%s yoga with %s %s" % (self.name,self.teacher,self.description) 
    def __repr__(self): 
     return str(self) 

# just make up some data to work with 
yoga_classes = (Yoga(1,"dynamic","mary","6pm"), 
       Yoga(1,"soft","susie","8pm"), 
       Yoga(3,"hatha","bob","5pm"), 
       Yoga(3,"hot","alice","7pm")) 

daylookup = (None,"Monday","Tuesday","Wednesday", 
      "Thursday","Friday","Saturday","Sunday") 

import itertools 
def get_classes(): 
    weekly_classes = [] 
    ycsorted = sorted(yoga_classes,key=lambda x: x.weekday) 
    for k,g in itertools.groupby(ycsorted,key=lambda x: x.weekday): 
     weekly_classes.append((daylookup[k],tuple(g))) 
    return weekly_classes 

import pprint 
pprint.pprint(get_classes())