Edit Dictionary in python

Question

I am beginner with python. I am getting something like following after writing a long block of code using regular expressions. Basically, I am creating dictionaries by using some kind of loops. Dictionary is of same name but only data is different.

my_dict= {'A':{'1':'a','2':'b'}} # created by loop1
my_dict= {'B':{'11':'ab','32':'pb'}} # created by loop2
my_dict= {'C':{'3':'sd','34':'cb'}} # created by loop3

Now as a final dictionary I want to get only one big dictionary which contains all data of above dictionaries. I want this big dictionary because in future I am gonna compare that with other big dictionary.

So my expected result looks like

my_dictionary={'A':{'1':'a','2':'b'} , 'B':{'11':'ab','32':'pb'} , 'C':{'3':'sd','34':'cb'} }

possible duplicate of [How can I merge (union) two Python dictionaries in a single expression?](http://stackoverflow.com/questions/38987/how-can-i-merge-union-two-python-dictionaries-in-a-single-expression) — Jon Gauthier, Sep 16 '14 at 20:18
@sam does any of answers satisfies what you are looking for in your question? — Dalek, Sep 19 '14 at 12:10

agconti · Accepted Answer · 2014-09-16T21:41:24.227

Just use update():

>>> my_dict= {'C':{'3':'sd','34':'cb'}} # created by loop3
>>> my_big_dict = {}
>>> my_big_dict.update(my_dict)
>>> my_big_dict
{'C': {'3': 'sd', '34': 'cb'}}

Example with a loop:

my_big_dict = {}
for i in range(0, 10):
    # create your dict
    my_dict= {'A':{'1':'a','2':'b'}}
    my_big_dict.update(my_dict)

To safely update the keys of the dictionary, ie. if you know you'll have multiple keys with different values like:

[{'A':{'1':'a','2':'b'}},
 {'A':{'3':'Z'}}]

Use:

dicts = [
    {'A':{'1':'a','2':'b'}}, 
    {'B':{'11':'ab','32':'pb'}},
    {'C':{'3':'sd','34':'cb'}},
    {'A':{'3':'Z'}},
    {'C':{'6':'sd','7':'cb'}},
    {'A':{'3':'XX'}},]

for d in dicts:
    for key, values in d.iteritems():
        if my_big_dict.has_key(key):
            my_big_dict[key].update(values)
            break 
        my_big_dict.update(d)

print my_big_dict     
#=> {'A': {'1': 'a', '3': 'Z', '2': 'b'}, 'C': {'3': 'sd', '6': 'sd', '7': 'cb', '34': 'cb'}, 'B': {'11': 'ab', '32': 'pb'}}

Using just my_big_dict.update(your_dict) will overwrite the stored dictionary, so you'll need handle the case the the key already exists.

This will just overwrite the existing dictionary with the key `A`, But the idea is right. — karthikr, Sep 16 '14 at 20:22

score 1 · Answer 2 · answered Sep 16 '14 at 20:28

You can try following. Before entering loop create an empty instance of dictionary.

my_dictionary  = dict()

While iterating through the loop just assignee dictionary key / value pairs.

my_dictionary['A'] = {'1':'a','2':'b'}
my_dictionary['B'] = {'11':'ab','32':'pb'}
my_dictionary['C'] = {'3':'sd','34':'cb'}

>>> my_dictionary
{'A': {'1': 'a', '2': 'b'}, 'C': {'3': 'sd', '34': 'cb'}, 'B': {'11': 'ab', '32': 'pb'}}

score 0 · Answer 3 · answered Sep 16 '14 at 20:47

if we assume each dictionary has a counter suffix in its name:

my_dict1= {'A':{'1':'a','2':'b'}} # created by loop1
my_dict2= {'B':{'11':'ab','32':'pb'}} # created by loop2
my_dict3= {'C':{'3':'sd','34':'cb'}} # created by loop3

my_dictionary = dict()
for i in range(0, 3):
    my_dictionary.update(eval('my_dict%d' %(i+1)))

Edit Dictionary in python

3 Answers3