How to combine the dictionaries in python

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I have 2 dictionaries

dict1 = {'color': {'attri': ['Black']}, 'diameter': {'attri': ['(300, 600)']}}

dict2 = {'size': {'op':'in'}, 'diameter': {'op':'range'}, 'color': {'op':'in'}}

I want to combine the 2 dictionaries such that

dict3 = {'color': {'op': 'in', 'attri': ['Black']}, 'diameter': {'op': 'range', 'attri': ['(300,600)']}}

Just use a mix of dict comprehensions and dict unpacking:

dict1 = {'color': {'attri':['Black']}, 'diameter': {'attri':['(300, 600)']}}
dict2 = {'size': {'op':'in'}, 'diameter': {'op':'range'}, 'color': {'op':'in'}}

dict3 = {n:{**dict1[n],**dict2[n]} for n in dict1}

Python, In this article, we will discuss few ways of merging dictionaries. Using the method Python code to merge dict using update() method. def Merge(dict1, dict2):. In Python, the Dictionary class provides a function update() i.e. It accepts an another dictionary or an Iterable object (collection of key value pairs) as argument. Then merges the contents of this passed dictionary or Iterable in the current dictionary. Let’s use this update() function to merge two dictionaries.

This method uses a defaultdict and is safe even if a key only appears in one of the dictionaries.

import itertools
import collections

dict3 = collections.defaultdict(dict)

for key, value in itertools.chain(dict1.items(), dict2.items()):
     dict3[key].update(value)

Proof -- applied to:

dict1 = {'color': {'attri':['Black']}, 'diameter': {'attri':['(300, 600)']}}
dict2 = {'size': {'op':'in'}, 'diameter': {'op':'range'}, 'color': {'op':'in'}}

the output of dict(dict3) is:

{'color': {'attri': ['Black'], 'op': 'in'},
'diameter': {'attri': ['(300, 600)'], 'op': 'range'},
'size': {'op': 'in'}}

Although looking at your expected output, you only want a result if the key appears in both dictionaries, in which case I'd do:

for key in set(itertools.chain(dict1, dict2)):
    if key in dict1 and key in dict2:
         dict3[key] = {**dict1, **dict2}

Python add to Dictionary, key. Note that if the key already exists, then the value will be overwritten. Python | Merging two Dictionaries Using the method update () By using the method update () in Python, one list can be merged into another. Using ** in Python This is generally considered a trick in Python where a single expression is used to merge two dictionaries and stored in

res = {}
for item in dict1:
  res.setdefault(item, {})
  res[item].update(dict1[item])
  if item in dict2:
    res[item].update(dict2[item])

Python Dictionary(Dict): Update, Cmp, Len, Sort, Copy, Items, str , How do I convert a list to a dictionary in python? Merge Dictionaries in Python Problem statement. We have two dictionaries representing two BUs (business units) of an IT company. By updating dictionaries cumulatively. The most obvious way to combine the given dictionaries is Merge dictionaries using unpacking operator. Combine two or more

For dictionaries x and y, z becomes a merged dictionary with values from y and from x.

In Python 3.5 or greater, :

z = {**x, **y}

In Python 2, (or 3.4 or lower) write a function:

def merge_two_dicts(x, y):
    z = x.copy()   # start with x's keys and values
    z.update(y)    # modifies z with y's keys and values & returns None
    return z
and

z = merge_two_dicts(x, y)

Python, Have you ever wanted to combine two or more dictionaries in Python? There are multiple ways to solve this problem: some are awkward, some  How to Merge Dictionaries in Python. In Python 3.5, you can merge two or more dictionaries in a single statement by unpacking the new dictionaries into a new dictionary. Start with two or more dictionaries: grades1 = {'Math': 98, 'Science': 87, 'English': 93} grades2 = {'Spanish': 94, 'Gym': 79, 'Science': 91}.

The Idiomatic Way to Merge Dictionaries in Python, How can I merge two Python dictionaries in a single expression? For dictionaries x and y , z becomes a shallowly merged dictionary with values from y replacing  Two dictionaries can be merged by using copy() and update() methods in python. Here, the original values of the dictionary will be unchanged. mergeDic() function is defined to copy the values of the first dictionary in a variable named merged and add the values of the second dictionary in merged.

How do I merge two dictionaries in a single expression in Python , In this short tutorial, you will learn how to combine two dictionaries together in Python using Duration: 1:29 Posted: Jun 6, 2018 Our code has two dictionaries: user and defaults. We want to merge these two dictionaries into a new dictionary called context. We have some requirements: user values should override defaults values in cases of duplicate keys. keys in defaults and user may be any valid keys. the values in defaults and user can be anything.

How to combine two dictionaries in Python, In a previous tutorial we learned about Python Dictionaries, and saw that they are considered unordered sets with a key/value pair, where keys  How to Combine Two Dictionary in Python. If you want to append the elements of the second dictionary after the elements of first. You can use the below-given method which put together the two dictionary elements. To perform this task, you have to put two dictionary variable in comma separation. Also, add the double asterisk(**) to both the variables.

Comments
  • check this link answer is already there link
  • @ashishpal That's not the same thing
  • Thanks This is working, How can I also do this if dict1 = {'color': ['Black'], 'diameter': ['(300, 600)']}
  • @AakashPatel What should happen then?
  • I am getting the following error :Traceback (most recent call last): File "C:/Users/AAKASH PATEL/Desktop/demo1.py", line 4, in <module> dict3 = {n:{**dict1[n],**dict2[n]} for n in dict1} File "C:/Users/AAKASH PATEL/Desktop/demo1.py", line 4, in <dictcomp> dict3 = {n:{**dict1[n],**dict2[n]} for n in dict1} TypeError: 'list' object is not a mapping
  • @AakashPatel Yes, because list can't be unpacked like that. It doesn't make sense to transform a list to a dict. What do you expect to happen?
  • Thanks This is working, How can I also do this if dict1 = {'color': ['Black'], 'diameter': ['(300, 600)']}
  • This isn't what OP wants. Look at the expected result of dict3.