Dictionary with set python

Python Dictionary of sets

In this Python tutorial, we will study how to create a dictionary from sets using some examples in python. Moreover, we will also cover these topics.

• Python Dictionary of sets
• Python dictionary of lists
• Python dictionary of lists append
• Python dictionary sets of Keys
• Python dictionary set value
• Python dictionary setdefault
• Python dictionary set list tuple
• Python dictionary of two lists
• Python dictionary with list to CSV
• Python dictionary set empty
• Python reverse dictionary of lists
• Python dictionary of lists to list
• Python dictionary keys to set
• Python dictionary values to set

Python Dictionary of sets

• In this section, we will discuss how to create a dictionary from sets in Python.
• To perform this particular task, we are going to import the defaultdict() module and then we will assign the key varaible in the list along with values as a dictionary form.
• In Python, the defaultdict() is similar to a dictionary but it is declared as a function and it takes no arguments, and also it will never raise an error.

Here is the Syntax of defaultdict() method.

defaultdict(defaultfactory)

Let’s take an example and check how to create a dictionary from two sets in Python.

Source Code:

from collections import defaultdict new_dict = defaultdict(set) new_dict["Employees_id"] |= new_dict["Employee_age"] |= print("Creation of dictionary from two sets:",new_dict)

Here is the execution of the following given code.

Python dictionary of lists

• In this Program, we will discuss how to create a dictionary from lists in Python.
• To do this task, we are going to insert a list as a value in the dictionary by using the subscript() method.

empty_dict = <> empty_dict["Country_name"] = ['USA', 'France'] empty_dict["Student_name"] = ['George', "James", "William"] print("Created dictionary of lists:",empty_dict)

Here is the execution of the following given code.

Python dictionary of lists append

We have already covered this topic in the Python dictionary of lists. You can refer to our detailed article at the above link.

Python dictionary sets of Keys

• In this section, we will discuss how to create a dictionary from sets of keys in Python.
• To do this task first we will create a list and assign the country name as a key element and then we are going to use the dict.fromkeys() method and it will return the keys along with none value.

Set_of_keys = ['Germany', 'France', 'Spain'] result = dict.fromkeys(Set_of_keys, None) print(result) 

Here is the Screenshot of the following given code

Python dictionary set value

• In this Program, we will discuss how to create a dictionary by set values in Python.
• To do this task, we are going to use the subscript method and this method will help the user to create a dictionary from a set of values.

new_dict = <> new_dict["USA"] = [16, 28, 39] new_dict["United Kingdom"] = [56, 98, 113] new_dict["France"] = [32, 87, 44] new_dict["Germany"] =[14,56,92] print("Created dictionary from set values:",new_dict)

In the above code first, we have created an empty dictionary for inserting the values in it and then we declare a specific key along with a set of values. Once you will execute this code the output displays the new dictionary that contains elements in the form of key-value pairs.

Here is the implementation of the following given code.

Python dictionary setdefault

• In this section, we will discuss how to use the setdefault method in Python dictionary.
• In Python, the setdefault() method returns the value of a key associated with a specified key. It will check the condition if the key is available in the dictionary then it will return value else if the key is not available in the dictionary and no default value is given then it will return none value.
• This method takes two arguments the key and the default value and this function are similar to the get() function.

Here is the Syntax of setdefault() function in Python.

• It consists only two major parameters
  • key: This parameter indicates the key which we want to be searched.
  • default: This parameter is used when the key is not available then it will return the value.

  Note: This method always returns the key-value elements which are available in the dictionary.

  Let’s take an example and check how to use the setdefault method in Python Dictionary.

  Source Code:

  Country_name= result=Country_name.setdefault('China') #key is available print(result) # if the key is not available not_key=Country_name.setdefault('Japan') print(not_key)

  Here is the implementation of the following given code.

  

  Python dictionary set list tuple

  • Here we are going to discuss how to create a dictionary from list of tuples in Python.
  • To perform this particular task, first, we are going to create a list of tuples and then we will use the dict() method and this method will easily convert the given list of tuples into the dictionary.
  • In Python, the dict() is a constructor that will help the user to create a dictionary from any object like tuples, lists, etc.

  Let’s take an example and check how to create a dictionary from a list of tuples in Python.

  Source Code:

  lis_of_tup = [('George', 156), ('William', 678), ('Oliva', 789), ('Elijah', 954), ('James', 222),('John',765)] new_output = dict(lis_of_tup) print("Conversion of list of tuples into dictionary:",new_output)

  Here is the Screenshot of the following given code.

  

  Python dictionary of two lists

  • In this section, we will discuss how to create a dictionary from two lists in Python.
  • To do this task, we are going to use the dict() and zip() method and this method will help the user to convert the given two lists into the dictionary.
  • In Python, the zip() function joins two iterable objects and the objects can be listed or tuple this method takes one or more iterables as an argument and always returns an iterator of tuples based on the given objects.

  Let’s have a look at the Syntax and understand the working of the Python zip() function.

  Let’s take an example and check how to create a dictionary from two lists in Python.

  Source Code:

  lis1=['USA','Australia','Germany','UnitedKingdom'] lis2=[12,34,56,78] new_result=dict(zip(lis1,lis2)) print("Conversion of two lists into dictionary:",new_result)

  Here is the implementation of the following given code.

  

  Python dictionary with list to CSV

  • In this example, we will discuss how to convert the dictionary with a list into CSV in Python.
  • To do this task, first, we will create a dictionary that contains elements in the form of key-value pairs and the values can be stored in a list.
  • In this example, we will use the CSV module and load the dictionary into a CSV file. To do this we will use the open() method.

  import csv my_dict = with open("final.csv", 'w') as outfile: dict_csv = csv.writer(outfile) dict_csv.writerow(my_dict.keys()) dict_csv.writerows(zip(*my_dict.values()))

  Here is the Screenshot of the CSV file in which keys and values are associated.

  

  Python dictionary set empty

  • In this section, we will discuss how to create an empty set in a Python dictionary.
  • To do this task, first, we will initialize an empty dictionary by using the curly braces<> and once you will execute this code the output displays the empty dict along with datatype.
  • Next, we will create an empty set by using the set keyword along with open braces(). Once you will execute this code the output displays the set datatype.

  new_var = <> print("Initialize dictionary:",type(new_var)) new_var = set() print("Initialize empty set:",type(new_var))

  Here is the Screenshot of the following given code

  

  Python reverse dictionary of lists

  • In this Program, we will discuss how to reverse the dictionary of lists in Python.
  • To perform this particular task, we are going to use the dictionary comprehension method in which we will use the dict.items() method.

  new_dict= result= print(result)

  Here is the execution of the following given code

  

  As you can see in the Screenshot the output displays the reverse of list values.

  Python dictionary of lists to list

  • In this section, we will discuss how to convert the dictionary of lists to a Python list.
  • To perform this particular task first we will create a dictionary named ‘my_dictionary’ that contains elements in the form of key-value pair and the values will be considered as list and then we will use the dictionary comprehension method.

  my_dictionary = new_output = [[new_k] + new_value for new_k, new_value in my_dictionary.items()] print(new_output)

  You can refer to the below Screenshot.

  

  Python dictionary keys to set

  • In this section, we will discuss how to extract keys from the dictionary and store them into a Python set.
  • First, we will initialize two dictionaries, and then by using the union | method we can easily extract the key elements from the dictionary and store them into a list.

  new_dict1 = new_dict2 = new_result = new_dict1.keys() | new_dict2.keys() #Extract keys and store in set print(new_result) print(type(new_result))

  Once you will execute this code the output displays the key elements in the form of a set along with we have mentioned the datatype of that result.

  Here is the implementation of the following given code.

  

  Python dictionary values to set

  • Here we are going to discuss how to extract values from the dictionary and store them into a Python set.
  • In this program, we have created a dictionary that contains elements and then we will use the dictionary comprehension method along with dict.items() method.
  • After extracting the key elements we are going to iterate those values and store them into the list.

  my_dict = new_result=.keys() s = set() for i in new_result: s.add(i) print(s) print(type(s)) 

  Here is the output of the following given code.

  

  You may also like to read the following Python tutorials.

  In this Python tutorial, we have studied how to create a dictionary from sets using some examples in python. Moreover, we have also covered these topics.

  • Python Dictionary of sets
  • Python dictionary of lists
  • Python dictionary of lists append
  • Python dictionary sets of Keys
  • Python dictionary set value
  • Python dictionary setdefault
  • Python dictionary set list tuple
  • Python dictionary of two lists
  • Python dictionary with list to CSV
  • Python dictionary set empty
  • Python reverse dictionary of lists
  • Python dictionary of lists to list
  • Python dictionary keys to set
  • Python dictionary values to set

  I am Bijay Kumar, a Microsoft MVP in SharePoint. Apart from SharePoint, I started working on Python, Machine learning, and artificial intelligence for the last 5 years. During this time I got expertise in various Python libraries also like Tkinter, Pandas, NumPy, Turtle, Django, Matplotlib, Tensorflow, Scipy, Scikit-Learn, etc… for various clients in the United States, Canada, the United Kingdom, Australia, New Zealand, etc. Check out my profile.

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  How can I perform set operations on Python dictionaries?

  While it is incredibly useful to be able to do set operations between the keys of a dictionary, I often wish that I could perform the set operations on the dictionaries themselves. I found some recipes for taking the difference of two dictionaries but I found those to be quite verbose and felt there must be more pythonic answers.

  5 Answers 5

  tl;dr Recipe: and | can be replaced with any other set operator.

  Based @torek’s comment, another recipe that might be easier to remember (while being fully general) is: .

  My first answer didn’t deal correctly with values that evaluated to False. Here’s an improved version which deals with Falsey values:

  >>> d1 = >>> d2 = >>> >>> print "d1 - d2:", # 0 d1 - d2: >>> print "d2 - d1:", # 1 d2 - d1: >>> print "intersection:", # 2 intersection: >>> print "union:", # 3 union:

  The version for union is the most general and can be turned into a function:

  >>> def dict_ops(d1, d2, setop): . """Apply set operation `setop` to dictionaries d1 and d2 . . Note: In cases where values are present in both d1 and d2, the value from . d1 will be used. . """ . return . >>> print "d1 - d2:", dict_ops(d1, d2, lambda x,y: x-y) d1 - d2: >>> print "d2 - d1:", dict_ops(d1, d2, lambda x,y: y-x) d2 - d1: >>> import operator as op >>> print "intersection:", dict_ops(d1, d2, op.and_) intersection: >>> print "union:", dict_ops(d1, d2, op.or_) union:

  Where items are in both dictionaries, the value from d1 will be used. Of course we can return the value from d2 instead by changing the order of the function arguments.

  >>> print "union:", dict_ops(d2, d1, op.or_) union:

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