I am trying to create a dictionary in python. To be more specific I want to read the input from the keyboard and then add it to dictionary. I am new to python and I don't know how can this be achieved.
for i in range(3)
key=input("Give key\n")
name=input("Give name\n")
#add these values in a dictionary
At first create empty dict:
d = {}
and then set values:
for i in range(3)
key=input("Give key\n") # use raw_input in python 2x
name=input("Give name\n")
d[key] = name
You can create a dictionary with
myDict = dict()
Set a value in it by
myDict[myKey] = 'myValue'
Read a value from it with
myDict[myKey] #Result: 'myValue'
Check whether a key exists in a dictionary with
myKey in myDict #Evaluates to a bool
For your problem:
Create a dictionary outside your loop
Add each entered value at the desired index as I showed you above.
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 am trying to create a menu from a nested dictionary. I can make it run using individual if statements for a static dictionary however, I would like to be able to append new key/value pairs to the dictionary without writing new if statements for the updated key/value pairs. Here's what I tried:
for entry in dict_key:
print(entry)
iquant = input(">")
for entry in dict_key:
if iquant == dict_key:
add = int(input(">"))
idict[idict_key] += add
It runs but passes to the line of code under the second for loop without taking an input.
if you want add news items in dic
for add new item in dic is
dic.update({
"nameKeyValue": "Value"
})
for remove item in dic is
dic.pop("nameKeyValue")
for edit value item in dic is
dic["namekey"] = value;
example:
dic = {
"data1","data1",
"data2","data2"
}
keyname = input("KeyName: ")
value = input("Value: ")
dic.update({
keyname:value
})#add item
dic.pop(keyname) #delete item
dic[keyname] = value #update data item
I have created a python dictionary with a structure like :-
mydict = {'2018-08' : [32124,4234,23,2323,32423,342342],
'2018-07' : [13123,23424,2,3,4343,4232,2342],
'2018-06' : [1231,12,12313,12331,3123131313,434546,232]}
I want to check if any value in the values of key '2018-08' match with any values of other keys. is there a short way to write this?
You can simply loop over your expected values of mydict, and then for each of them check if its present in any of the values of the dictionary
You can use the idiom if item in list to check if item item is present in the list list
expected_values = mydict['2018-08']
found = False
for expected in expected_values:
for key in mydict:
if expected in mydict[key]:
found = True
break
Take into account that is a brute force algorithm and it may not be the optimal solution for larger dictionaries
The question is vague, so I am assuming that you want the values in the target month (e.g. 2018-08) that are contained somewhere within the other months.
Sets are much faster for testing membership compared to list iteration.
target = '2018-08'
s = set()
for k, v in mydict.iteritems():
if k != target:
s.update(v)
matches = set(mydict[target]) & s
Can use itertools.chain to create a long list
import itertools
for key,value in mydict.items():
temp_dict = mydict.copy()
temp_dict.pop(key)
big_value_list=list(itertools.chain(*temp_dict.values()))
print(key, set(value) & set(big_value_list))
Dry run by changing your provided inputs
mydict = {'2018-08' : [32124,4234,23,2323,32423,342342],
'2018-07' : [13123,23424,2,3,4343,4232,2342],
'2018-06' : [1231,12,12313,12331,3123131313,434546,232,342342,2342]}
Output:
('2018-08', set([342342]))
('2018-07', set([2342]))
('2018-06', set([342342, 2342]))
I am not sure if thats what i really want but i want this structure basically,
-document
-pattern_key
-start_position
-end_position
right now i have this
dictionary[document] = {"pattern_key":key, "startPos":index_start, "endPos": index_end}
but i want to nest startPos, endPos under pattern key
Also how can i update this, to add a new entry of pattern_key, startPos, endPos, under same document?
with this you can updates values of the keys
for x in dict.keys():
if 'pattern_key' in x:
dict[x]= 'new value'
if 'endPost'...
.....
print dict
>>> should have new values
for add new entrys:
old = {}
old['keyxD'] = [9999]
new = {}
new['newnewnew'] = ['supernewvalue']
new.update(old)
print new
>>>{'newnewnew': ['supernewvalue'], 'keyxD': [9999]}
Not sure what you exactly want, but you can try this:
document = {'pattern_key' : {}}
This created an object document which is a dictionary, where the key is a string (pattern_key) and the value is another dictionary. Now, to add new entries to the value of the dictionary (which is another dictionary) you just add your values:
document['pattern_key']['start_position'] = 1
document['pattern_key']['end_position'] = 10
Afterwards, you can enter either case with document['pattern_key']['start_position'] = 2 and this will change the start position to 2.
Hope this helps
I'm having a bit of a problem, don't even know if this is doable. I have a number of launchers that each have a interface defined with the expected inputs. The input values come as a dictionary. For example:
dict_key = str(req_input[0]['name'])
data = dict(dict_key = value)
Now req_input[0]['name'] is the key I would like to insert into the dictionary. Now I know what I'm doint here only creates a dictionary of the form {'dict_key' : value} but I was wondering if it is possible to create the dicionary as to be the form {'Actual value of dict_key' : value}
Regards,
Bogdan
The best way to do this is simply using the dict literal {}:
data = {dict_key: value}
Other ways would be
data = dict({dict_key: value})
or
data = dict()
data[dict_key] = value
but these are longer so stay with the first one.
Another way is:
data = {}
data[req_input[0]['name']] = value
This way you can add multiple values to the same dictionary, or loop through req_input if you have multiple parameters there, i.e.:
data = {}
for input in req_input:
data[input['name']] = value