迭代列表并将其值与dict比较

Question

I am dealing with 1. list of dictionaries and 2. list. I am trying to:
1. iterate through list (list1),
2. Match the list1's value with the ID of API response, if found- put entire dict in a new_dict 3. else skip

API response in Json format:

   list_of_dict=[{"id":1500,
      "f_name": "alex",
       "age": 25
      },

      {"id" :1501,
       "f_name":"Bob",
       "age": 30
      },
      {"id" :1600,
       "f_name":"Charlie",
       "age": 35
      }
      ...
     ]

And a list1:

list1=[1500,1501,1211.....]

According to this, 1500 & 1501 is present in list_of_dict so that entire dict will be added in new_dict.

My attempt:

new_dict=dict()
for i,val in enumerate(list1):
    #assuming val found in dict
    #so put it in new dict
    print i ,"=",val
    new_dict.update({"id": val,"name":name, "age":age})

What i see is this code taking only last item of the list and updates the dict.. but in my case, new_dict will contains two dictionaries with id 1500 and 1501 . What i am missing?

Answer 1

    list_of_dict = [{"id":1500,
                     "f_name": "alex",
                     "age": 25
                     },

                     {"id" :1501,
                      "f_name":"Bob",
                      "age" 30
                     },
                     {"id" :1600,
                      "f_name":"Charlie",
                      "age" 35
                     }
                     ...
                  ]

dicts = {d['id']:d for d in list_of_dict}
list1=[1500,1501,1211.....]

answer = [dicts[k] for k in list1 if k in dicts]

Answer 2

list_of_dict = [{"id":1500,
                     "f_name": "alex",
                     "age": 25
                     },

                     {"id" :1501,
                      "f_name":"Bob",
                      "age": 30
                     },
                     {"id" :1600,
                      "f_name":"Charlie",
                      "age": 35
                     }
                  ]

list1=[1500,1501,1211]

ret = filter(lambda x: x['id'] in list1, list_of_dict)
print ret

Check out the useful and simple filter function built-in to python. It iterates through an iterable (list) and returns only the items that return true for the provided function

In this case, our filtering function is:

lambda x: x['id'] in list1

Answer 3

You can do this with a simple list comprehension, filtering the dicts by whether their id is in the list:

result = [d for d in list_of_dict if d["id"] in list1]

If your list1 is larger, you might want to turn it into a set first, so the lookup is faster:

list1_as_set = set(list1)
result = [d for d in list_of_dict if d["id"] in list1_as_set]