从python字典和复杂列表中提取元素

Question

我有一份清单，上面列出了一些代表纽约地铁车辆的清单和字典：

[[{'arrival': {'time': 1506873749L},
   'departure': {'time': 1506873749L},
   'schedule_relationship': 0,
   'stop_id': u'B20S'},
  {'arrival': {'time': 1506873854L},
   'departure': {'time': 1506873854L},
   'schedule_relationship': 0,
   'stop_id': u'B21S'},
  {'arrival': {'time': 1506873989L},
   'departure': {'time': 1506873989L},
   'schedule_relationship': 0,
   'stop_id': u'B22S'},
  {'arrival': {'time': 1506874184L},
   'departure': {'time': 1506874184L},
   'schedule_relationship': 0,
   'stop_id': u'B23S'},
  {'arrival': {'time': 1506874469L},
   'departure': {'time': 1506874469L},
   'schedule_relationship': 0,
   'stop_id': u'D43S'}],
 [{'arrival': {'time': 1506873814L},
   'departure': {'time': 1506873814L},
   'schedule_relationship': 0,
   'stop_id': u'D10N'},
  {'arrival': {'time': 1506873877L},
   'departure': {'time': 1506873877L},
   'schedule_relationship': 0,
   'stop_id': u'D09N'},
  {'arrival': {'time': 1506873997L},
   'departure': {'time': 1506873997L},
   'schedule_relationship': 0,
   'stop_id': u'D08N'},
  {'arrival': {'time': 1506874087L},
   'departure': {'time': 1506874087L},
   'schedule_relationship': 0,
   'stop_id': u'D07N'},
  {'arrival': {'time': 1506874177L},
   'departure': {'time': 1506874177L},
   'schedule_relationship': 0,
   'stop_id': u'D06N'},
  {'arrival': {'time': 1506874267L},
   'departure': {'time': 1506874267L},
   'schedule_relationship': 0,
   'stop_id': u'D05N'},
  {'arrival': {'time': 1506874357L},
   'departure': {'time': 1506874357L},
   'schedule_relationship': 0,
   'stop_id': u'D04N'},
  {'arrival': {'time': 1506874477L},
   'departure': {'time': 1506874477L},
   'schedule_relationship': 0,
   'stop_id': u'D03N'},
  {'arrival': {'time': 1506874627L},
   'departure': {'time': 1506874627L},
   'schedule_relationship': 0,
   'stop_id': u'D01N'}]]

我正在尝试识别与特定stop_id关联的条目。例如，如果我搜索的是'D03N'，我希望返回与之关联的整个条目：

^{pr2}$

不幸的是，每当我尝试使用这个答案中的建议：Python list of dictionaries search 最后我得到了一条“TypeError:list index must be integers，not str”错误消息。我不确定这是因为我错误地实现了这个解决方案，还是因为这个方案与原始问题中的列表相比相对复杂，所以这个方案不适用。在

有没有办法从这个列表中抽出具体的条目？在

Answer 1

>>> from itertools import chain
>>> data = [[{'arrival': {'time': 1506873749L}, 'departure': {'time': 1506873749L}, 'schedule_relationship': 0, 'stop_id': u'B20S'}, {'arrival': {'time': 1506873854L}, 'departure': {'time': 1506873854L}, 'schedule_relationship': 0, 'stop_id': u'B21S'}, {'arrival': {'time': 1506873989L}, 'departure': {'time': 1506873989L}, 'schedule_relationship': 0, 'stop_id': u'B22S'}, {'arrival': {'time': 1506874184L}, 'departure': {'time': 1506874184L}, 'schedule_relationship': 0, 'stop_id': u'B23S'}, {'arrival': {'time': 1506874469L}, 'departure': {'time': 1506874469L}, 'schedule_relationship': 0, 'stop_id': u'D43S'}], [{'arrival': {'time': 1506873814L}, 'departure': {'time': 1506873814L}, 'schedule_relationship': 0, 'stop_id': u'D10N'}, {'arrival': {'time': 1506873877L}, 'departure': {'time': 1506873877L}, 'schedule_relationship': 0, 'stop_id': u'D09N'}, {'arrival': {'time': 1506873997L}, 'departure': {'time': 1506873997L}, 'schedule_relationship': 0, 'stop_id': u'D08N'}, {'arrival': {'time': 1506874087L}, 'departure': {'time': 1506874087L}, 'schedule_relationship': 0, 'stop_id': u'D07N'}, {'arrival': {'time': 1506874177L}, 'departure': {'time': 1506874177L}, 'schedule_relationship': 0, 'stop_id': u'D06N'}, {'arrival': {'time': 1506874267L}, 'departure': {'time': 1506874267L}, 'schedule_relationship': 0, 'stop_id': u'D05N'}, {'arrival': {'time': 1506874357L}, 'departure': {'time': 1506874357L}, 'schedule_relationship': 0, 'stop_id': u'D04N'}, {'arrival': {'time': 1506874477L}, 'departure': {'time': 1506874477L}, 'schedule_relationship': 0, 'stop_id': u'D03N'}, {'arrival': {'time': 1506874627L}, 'departure': {'time': 1506874627L}, 'schedule_relationship': 0, 'stop_id': u'D01N'}]]

>>> def find(s):
        found = [x for x in chain(*data) if x['stop_id']==s]
        return found[0] if found else None

>>> find(u'D03N')
{'arrival': {'time': 1506874477L}, 'schedule_relationship': 0, 'departure': {'time': 1506874477L}, 'stop_id': u'D03N'}

Answer 2

这里是一个递归的解决方案，可以处理任何级别的嵌套列表。 此函数搜索（DFS）列表，就像它是一个图形，其中列表是根节点，子列表是父节点，字典是叶子节点。在

def find_by_stopid(at, target, saveto):
    if isinstance(at, dict):
        if at['stop_id'] == target:
            saveto.append(at)
        return

    for x in at:
        find_by_stopid(x, target, saveto)

found = []
target = u'D03N'

# data is the list you have, targets is the string to match
# and found is where matches are saved
find_by_stopid(data, target, found)

print(found)

Answer 3

l = <your list>
[ i for i in sum(l,[]) if i['stop_id'] == 'D03N' ]

或者更有效的方法

^{pr2}$