i'm using an api call in python 3.7 which returns json data.
result = (someapicall)
the data returned appears to be in the form of two nested dictionaries within a list, i.e.
[{name:foo, firmware:boo}{name:foo, firmware:bar}]
i would like to retrieve the value of the key "name" from the first dictionary and also the value of key "firmware" from both dictionaries and store in a new dictionary in the following format.
{foo:(boo,bar)}
so far i've managed to retrieve the value of both the first "name" and the first "firmware" and store in a dictionary using the following.
dict1={}
for i in result:
dict1[(i["networkId"])] = (i['firmware'])
i've tried.
d7[(a["networkId"])] = (a['firmware'],(a['firmware']))
but as expected the above just seems to return the same firmware twice.
can anyone help achive the desired result above
you can use defaultdict to accumulate values in a list, like this:
from collections import defaultdict
result = [{'name':'foo', 'firmware':'boo'},{'name':'foo', 'firmware':'bar'}]
# create a dict with a default of empty list for non existing keys
dict1=defaultdict(list)
# iterate and add firmwares of same name to list
for i in result:
dict1[i['name']].append(i['firmware'])
# reformat to regular dict with tuples
final = {k:tuple(v) for k,v in dict1.items()}
print(final)
Output:
{'foo': ('boo', 'bar')}
Related
If I have a list of dictionaries in a python script, that I intend to later on dump in a JSON file as an array of objects, how can I index the keys of a specific dictionary within the list?
Example :
dict_list = [{"first_dict": "some_value"}, {"second_dict":"some_value"}, {"third_dict": "[element1,element2,element3]"}]
My intuitive solution was dict_list[-1][0] (to access the first key of the last dictionary in the list for example). This however gave me the following error:
IndexError: list index out of range
the key inputted into the dictionary will pick the some value in the format dict = {0:some_value}
to find a specific value:
list_dictionary = [{"dict1":'value1'},{"dict2","value2"}]
value1 = list_dictionary[0]["dict1"]
the 'key' is what you have to use to find a value from a dictionary
Example:
dictionary = {0:value}
dictionary[0]
in this case it will work
but to pick the elements we will do
values = []
for dictionary in dict_list:
for element in dictionary:
values.append(dictionary[element])
Output:
['some_value', 'some_value', ['element1', 'element2', 'element3']]
dict_list = [{"first_dict": "some_value"}, {"second_dict":"some_value"}, {"third_dict": ['element1','element2','element3']}]
If your dict look like this you can do as well
dict_list[-1]["third_dict"]
You can't access 'the first key' with a int since you have a dict
You can get the first key with .keys() and then
dict_list[-1].keys()[0]
By using dict_list[-1][0], you are trying to access a list with a list, which you do not have. You have a list with a dict key within a list.
Taking your example dict_list[-1][0]:
When you mention dict_list you are already "in the list".
The first index [-1] is referring to the last item of the list.
The second index would only be "usable" if the item mentioned in the previous index were a list. Hence the error.
Using:
dict_list=[{"first_dict": "some_value"}, {"second_dict":"some_value"},{"third_dict": [0,1,2]}]
to access the value of third_dict you need:
for value in list(dict_list[-1].values())[0]:
print(value)
Output:
0
1
2
If you know the order of dictionary keys and you are using one of the latest python versions (key stays in same order), so:
dict_list = [
{"first_dict": "some_value"}
, {"second_dict":"some_value"}
, {"third_dict": ["element1", "element2", "element3"]}
]
first_key = next(iter(dict_list[-1].keys()))
### OR: value
first_value = next(iter(dict_list[-1].values()))
### OR: both key and value
first_key, first_value = next(iter(dict_list[-1].items()))
print(first_key)
print(first_key, first_value)
print(first_value)
If you have the following list of dictionaries:
dict_list = [{"key1":"val1", "key2":"val2"}, {"key10":"val10"}]
Then to access the last dictionary you'd indeed use dict_list[-1] but this returns a dictionary with is indexed using its keys and not numbers: dict_list[0]["key1"]
To only use numbers, you'd need to get a list of the keys first: list(dict_list[-1]). The first element of this list list(dict_list[-1])[0] would then be the first key "key10"
You can then use indices to access the first key of the last dictionary:
dict_index = -1
key_index = 0
d = dict_list[dict_index]
keys = list(d)
val = d[keys[key_index]]
However you'd be using the dictionary as a list, so maybe a list of lists would be better suited than a list of dictionaries.
I have a dictionary which looks as shown below. Now I need to get the key its corresponding path together so as to use it further to identify its slot number based on the key. How can I achieve that?
I tried an approach but it is giving me key error.
What you need can easily be implemented as:
>>> {key: value["mpath"] for key, value in multipath.items()}
{'/dev/sdh': '/dev/mapper/mpathk', '/dev/sdi': '/dev/mapper/mpathk',
'/dev/sdg': '/dev/mapper/mpathj', '/dev/sdf': '/dev/mapper/mpathj',
'/dev/sdd': '/dev/mapper/mpathi', '/dev/sde': '/dev/mapper/mpathi',
'/dev/sdb': '/dev/mapper/mpathh', '/dev/sdc': '/dev/mapper/mpathh',
'/dev/sdj': '/dev/mapper/mpathg', '/dev/sdk': '/dev/mapper/mpathg'}
Great one line answer by #Selcuk using dictionary comprehension.
An elaborated one along the same line would be:
mpath_dict = {}
for sd, mpath in multipath.items():
mpath_dict[sd] = mpath['mpath']
print(mpath_dict)
Since every value item of "mpath" dictionary is a dictionary itself, you can retrieve values from it as you would do it in a dictionary.
I have a list like this, i need to get the value of the dictionary for both the keys inside the dictionary(dict)
dict = [{'module': 'https://svn.domain.com/svn/reponame/branchname', 'revision': 22295}]
expected output :
https://svn.domain.com/svn/reponame/branchname
22295
Your dict is actually a dictionary within a list. Try:
print(dict[0]['module'])
print(dict[0]['revision'])
I have 2 dict, one original and one for mapping the original one's key to another value simultaneously,for instance:
original dict:
built_dict={'China':{'deportivo-cuenca-u20':{'danny':'test1'}},
'Germany':{'ajax-amsterdam-youth':{'lance':'test2'}}}
mapping dict:
club_team_dict={'deportivo-cuenca-u20':'deportivo','ajax-amsterdam-youth':'ajax'}
It works well if I use the following code to change the key of the nested dict of original dict,like
def club2team(built_dict,club_team_dict):
for row in built_dict:
# print test_dict[row]
for sub_row in built_dict[row]:
for key in club_team_dict:
# the key of club_team_dict must be a subset of test_dict,or you have to check it and then replace it
if sub_row==key:
built_dict[row][club_team_dict[sub_row]] = built_dict[row].pop(sub_row)
return built_dict
and the result:
{'Germany': {'ajax': {'lance': 'test2'}}, 'China': {'deportivo': {'danny': 'test1'}}}
so far so good, however if I have a dict with multiple key mapping to the same key,for example,my original dict is like
built_dict={'China':{'deportivo-cuenca-u20':{'danny':'test1'}},
'Germany':{'ajax-amsterdam-youth':{'lance':'test2'},
'ajax-amsterdam':{'tony':'test3'}}}
and the mapping dict with more then 1 key mapping to the same value,like:
club_team_dict={'deportivo-cuenca-u20':'deportivo',
'ajax-amsterdam-youth':'ajax',
'ajax-amsterdam':'ajax'}
as you can see, both 'ajax-amsterdam-youth'and 'ajax-amsterdam-youth' are mapping to 'ajax',and the trouble is when I use the same code to execute it, the original dict's size has been changed during the iteration
RuntimeError: dictionary changed size during iteration
I want to get a result with nested list for the same key like this
{'Germany': {'ajax':[{'lance': 'test2'},
{'tony' : 'test3'}]}},
'China': {'deportivo': [{'danny': 'test1'}]}}
Well I have found a solution for this,the code:
def club2team(built_dict,club_team_dict):
for row in built_dict:
# print test_dict[row]
for sub_row in built_dict[row].keys():
for key in club_team_dict:
# the key of club_team_dict must be a subset of test_dict,or you have to check it and then replace it
if sub_row==key:
# built_dict[row][club_team_dict[sub_row]] = built_dict[row].pop(sub_row)
built_dict[row].setdefault(club_team_dict[sub_row],[]).append(built_dict[row].pop(sub_row))
return built_dict
pay attention to the for sub_row in built_dict[row].keys(): and setdefault() method, I used to believe that in python 2.7, the default iteration for dict is just iterate the keys(), however, this time it proves it's a little different, maybe you have better solution, please show me and it will be appreciate,thank you
Here is my code:
for response in responses["result"]:
ids = {}
key = response['_id'].encode('ascii')
print key
for value in response['docs']:
ids[key].append(value)
Traceback:
File "people.py", line 47, in <module>
ids[key].append(value)
KeyError: 'deanna'
I am trying to add multiple values to a key. Throws an error like above
Check out setdefault:
ids.setdefault(key, []).append(value)
It looks to see if key is in ids, and if not, sets that to be an empty list. Then it returns that list for you to inline call append on.
Docs:
http://docs.python.org/2/library/stdtypes.html#dict.setdefault
If I'm reading this correctly your intention is to map the _id of a response to its docs. In that case you can bring down everything you have above to a dict comprehension:
ids = {response['_id'].encode('ascii'): response['docs']
for response in responses['result']}
This also assumes you meant to have id = {} outside of the outermost loop, but I can't see any other reasonable interpretation.
If the above is not correct,
You can use collections.defaultdict
import collections # at top level
#then in your loop:
ids = collections.defaultdict(list) #instead of ids = {}
A dictionary whose default value will be created by calling the init argument, in this case calling list() will produce an empty list which can then be appended to.
To traverse the dictionary you can iterate over it's items()
for key, val in ids.items():
print(key, val)
The reason you're getting a KeyError is this: In the first iteration of your for loop, you look up the key in an empty dictionary. There is no such key, hence the KeyError.
The code you gave will work, if you first insert an empty list into the dictionary under to appropriate key. Then append the values to the list. Like so:
for response in responses["result"]:
ids = {}
key = response['_id'].encode('ascii')
print key
if key not in ids: ## <-- if we haven't seen key yet
ids[key] = [] ## <-- insert an empty list into the dictionary
for value in response['docs']:
ids[key].append(value)
The previous answers are correct. Both defaultdict and dictionary.setdefault are automatic ways of inserting the empty list.