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A dictionary in python is a data construction that stores data in the form of key-value pairs. The key-value pairs are too called items. The key-value pairs in each lexicon are separated by a colon ":" and each particular in the dictionary is separated by a comma ",". In this article, we will look at different ways to add an item to a lexicon in python.

Add an item to a dictionary using subscript notation

If we take a dictionary named myDict and a key-value pair having values myKey and myValue, then we can add the key-value pair to the dictionary using the syntax myDict [ myKey ] = myValue. This can be done as follows.

            myDict = {"name": "PythonForBeginners", "acronym": "PFB"} impress("Original Lexicon is:", myDict) myDict["niche"] = "programming" impress("Modified Lexicon is:", myDict)          

Output:

            Original Dictionary is: {'name': 'PythonForBeginners', 'acronym': 'PFB'} Modified Dictionary is: {'name': 'PythonForBeginners', 'acronym': 'PFB', 'niche': 'programming'}          

In the example to a higher place, we accept added a new key "niche" with value "programming" associated with it.

Remember that if the key of the item which is being added to the dictionary already exists in it, the value for the key volition be overwritten with a new value. This tin can be seen in the following case.

            myDict = {'name': 'PythonForBeginners', 'acronym': 'PFB', 'niche': 'programming'} print("Original Dictionary is:", myDict) myDict["niche"] = "python programming" print("Modified Lexicon is:", myDict)          

Output:

            Original Dictionary is: {'proper noun': 'PythonForBeginners', 'acronym': 'PFB', 'niche': 'programming'} Modified Lexicon is: {'name': 'PythonForBeginners', 'acronym': 'PFB', 'niche': 'python programming'}          

In the case above, the cardinal "niche" already exists in the dictionary with value "programming" associated with it. When nosotros try to add the key-value pair with "niche" as key and "python programming" every bit associated value, the value associated with "niche" is updated to the new value.

Add an particular to a dictionary using the update() method in Python

Nosotros can add an item to a dictionary using the update() method. The update() method when invoked on a lexicon, takes a dictionary or an iterable object having key-value pairs equally input and adds the items to the dictionary.

We can requite a  new dictionary equally an input to the update() method and add the items to a given dictionary as follows.

            myDict = {"proper noun": "PythonForBeginners", "acronym": "PFB"} print("Original Dictionary is:", myDict) myDict.update({'niche': 'programming'}) print("Modified Lexicon is:", myDict)          

Output:

            Original Lexicon is: {'name': 'PythonForBeginners', 'acronym': 'PFB'} Modified Dictionary is: {'name': 'PythonForBeginners', 'acronym': 'PFB', 'niche': 'programming'}          

We can give a list of tuples having key-value pairs equally an input to the update() method and add items to a given dictionary as follows.

            myDict = {"name": "PythonForBeginners", "acronym": "PFB"} print("Original Lexicon is:", myDict) items = [("niche", "programming")] myDict.update(items) print("Modified Dictionary is:", myDict)          

Output:

            Original Dictionary is: {'proper noun': 'PythonForBeginners', 'acronym': 'PFB'} Modified Dictionary is: {'proper noun': 'PythonForBeginners', 'acronym': 'PFB', 'niche': 'programming'}          

We can likewise pass key-value pairs every bit keyword parameters to the update() method to add elements to the lexicon. Here the keys will be used as keyword parameters and values will be assigned as an input to the keyword parameters every bit follows.

            myDict = {"proper name": "PythonForBeginners", "acronym": "PFB"} print("Original Dictionary is:", myDict) myDict.update(niche="programming") print("Modified Lexicon is:", myDict)          

Output:

            Original Lexicon is: {'name': 'PythonForBeginners', 'acronym': 'PFB'} Modified Dictionary is: {'name': 'PythonForBeginners', 'acronym': 'PFB', 'niche': 'programming'}          

Add an item to a dictionary using the ** operator in Python

A double asterisk (**) operator is used to laissez passer variable length keyword parameters to a part. We tin can also utilize the ** operator to add a key-value pair to another dictionary. When nosotros employ the ** operator to a dictionary, it deserializes the dictionary and converts it to a collection of fundamental-value pairs. This collection of key-value pairs can be again converted to a lexicon.

To add an item to a dictionary, nosotros volition first create a dictionary with only that item. Then we volition use the ** operator to merge the new dictionary and the lexicon to which the item had to be added every bit follows.

            myDict = {"name": "PythonForBeginners", "acronym": "PFB"} print("Original Dictionary is:", myDict) newDict = {'niche': 'programming'} myDict = {**myDict, **newDict} print("Modified Dictionary is:", myDict)          

Output:

            Original Dictionary is: {'name': 'PythonForBeginners', 'acronym': 'PFB'} Modified Lexicon is: {'name': 'PythonForBeginners', 'acronym': 'PFB', 'niche': 'programming'}          

Add an item to a dictionary using the __setitem__() method

We tin also add an particular to the dictionary using the __setitem__() method. The __setitem__() method, when invoked on a lexicon, takes the new primal and value every bit its first and second parameters respectively and adds the key-value pair to the lexicon as follows.

            myDict = {"name": "PythonForBeginners", "acronym": "PFB"} print("Original Dictionary is:", myDict) myDict.__setitem__('niche', 'programming') impress("Modified Dictionary is:", myDict)          

Output:

            Original Dictionary is: {'name': 'PythonForBeginners', 'acronym': 'PFB'} Modified Dictionary is: {'name': 'PythonForBeginners', 'acronym': 'PFB', 'niche': 'programming'}          

If the primal already exists in the dictionary, the value associated with it is overwritten with the new value. This can be seen in the following example.

            myDict = {'proper name': 'PythonForBeginners', 'acronym': 'PFB', 'niche': 'programming'} impress("Original Lexicon is:", myDict) myDict.__setitem__('niche', 'python programming') print("Modified Dictionary is:", myDict)          

Output:

            Original Lexicon is: {'proper noun': 'PythonForBeginners', 'acronym': 'PFB', 'niche': 'programming'} Modified Dictionary is: {'name': 'PythonForBeginners', 'acronym': 'PFB', 'niche': 'python programming'}          

Determination

In this commodity, we have seen different ways to add together an item to a dictionary in python. To read more about dictionaries in python you can read this article on dictionary comprehension or this commodity on how to merge two dictionaries in python.

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