Python Dictionary(Dict): Update, Cmp, Len, Sort, Copy, Items, str Example
In Python, what exactly is a Dictionary?
An unordered and changeable collection of data values that contains key-value pairs is referred to as a Dictionary in Python. Each key-value pair in the dictionary maps the key to the value that corresponds to it, making the dictionary more efficient. Using curly brackets(), you may declare a Dictionary in Python by enclosing a collection of key-value pairs separated by commas in a single line. Python Dictionary is divided into two parts: Keys and Values. Keys are the names of the variables in the dictionary.
It is planned that keys will be a single element.
Values can be a list or a list within a list, numbers, or any other type of data.
In this Python lesson, you will learn how to do the following:
In Python, what exactly is a Dictionary?
Using the update() method, combine two dictionaries.
Using the ** technique to combine dictionaries (From Python 3.5 onwards)
Membership in a dictionary Python Dictionary Syntax Validation Test
Dict =’Tim’: 18, xyz, and so forth.
In curly brackets, a dictionary is listed, and within these curly brackets, the keys and values of the dictionary are declared. Commas divide each element from its key, and a colon (:) separates the key from its value for each key in the table.
Dictionary Keys Have Specific Characteristics
When employing dictionary keys, there are two significant considerations.
It is not permitted to make more than one entry per key ( no duplicate key is allowed)
The contents in the dictionary can be of any type, whereas the keys must be immutable, such as numbers, tuples, or strings, in order for the dictionary to work.
Dictionary keys are case sensitive; in Python dictionaries, the same key name with distinct case variations is treated as if it were two independent keys.
Python 2 Programming Demonstration
“Tim” is 18, “Charlie” is 12, “Tiffany” is 22, “Robert” is 25, and “Charlie” is 26. “Tiffany” is 22 and “Robert” is 25.
Python 3 Demonstration
Dict = ‘Tim’ (18), ‘Charlie’ (12), ‘Tiffany’ (22) and ‘Robert’ (25).
print((Dict[‘Tiffany’]))
The word “Dict” is used to refer to a dictionary in code.
We entered the person’s name and age into a dictionary, where name is represented by the letter “Keys” and age is represented by the letter “Value.”
Now, execute the code.
Tiffany’s age is retrieved from the dictionary using this function.
Using Python Dictionary Methods is a great way to get started with Python.
Making a copy of a dictionary
A copy of the full dictionary can also be made and saved in a new dictionary. Let us take the example of the following: we copied our original dictionary to the new dictionary names “Boys” and “Girls.”
Python 2 Programming Demonstration
Dict = ‘Tim’ (18), ‘Charlie’ (12), ‘Tiffany’ (22) and ‘Robert’ (25).
Boys = ‘Tim’ is 18, ‘Charlie’ is 12, and ‘Robert’ is 25.
Tiffany:22 is a girl’s name.
studentX=Boys.
copy() \sstudentY=Girls.
copy()
Python 3 Example: print studentX print studentY print studentZ
Dict = ‘Tim’ (18), ‘Charlie’ (12), ‘Tiffany’ (22) and ‘Robert’ (25).
Boys = ‘Tim’ is 18, ‘Charlie’ is 12, and ‘Robert’ is 25.
Tiffany:22 is a girl’s name.
studentX=Boys.copy() \sstudentY=Girls.copy()
print(studentX) \sprint(studentY)
We have the original dictionary (Dict), which has the names and ages of both boys and girls in the same list. However, we want the boys list to be distinct from the girls list, so we specified the elements of boys and girls in separate dictionary names “Boys” and “Girls,” respectively.
We have generated two new dictionary names “student X” and “student Y,” in which all of the keys and values from the boy dictionary are copied into student X, and all of the keys and values from the girl dictionary are copied into student Y.
Consequently, instead of having to go through the entire list in the main dictionary(Dict) to determine who is a boy and who is a girl, you can simply print student X if you want a boys list and StudentY for a females list from the main dictionary.
In other words, when you run the student X and studentY dictionary, it will return all of the elements that are present in the “boys” and “female” dictionaries. separately
Dictionary Updating and Maintenance
An existing entry can be updated by adding a new entry or by adding a key-value pair to an existing item, or by deleting an existing entry from the dictionary. In this example, we will add another name, “Sarah,” to our existing dictionary in order to demonstrate the concept.
Python 2 Programming Demonstration
Dict = ‘Tim’ (18), ‘Charlie’ (12), ‘Tiffany’ (22) and ‘Robert’ (25).
Dict.update({“Sarah”:9})
print Example of a Dict Python 3
Dict = ‘Tim’ (18), ‘Charlie’ (12), ‘Tiffany’ (22) and ‘Robert’ (25).
Dict.update({“Sarah”:9})
(Dict) The name “Sarah” does not appear in our existing dictionary, which is called “Dict.”
We utilise the Dict.update method to add Sarah to our existing dictionary, which we already have.
When we run the code, Sarah is automatically added to our existing dictionary.
Keys are removed from the dictionary.
When using the Python dictionary, you have the option of removing any element from the dictionary list. For example, if you don’t want the name Charlie to appear in the list, you can remove it by using the following code:
Python 2 Programming Demonstration
In Python 3, the variables Dict and Charlie are equal to 18, 12, 22, and 25 respectively. Dict = “Tim”:18, “Charlie”:12, “Tiffany”:22, “Robert”:25 del Dict [“Charlie”] print Dict Python 3 Example
Dict = ‘Tim’: 18,’Charlie’:12,’Tiffany’:22,’Robert’:25 del Dict [‘Charlie’] print Dict = ‘Tim’: 18,’Charlie’:12,’Tiffany’:22,’Robert’:25 del Dict [‘Charlie’] print (Dict)
When you run this code, the dictionary list should be printed without Charlie’s name in it.
We made use of the Dict code.
During the execution of the code, it erased the character Charlie from the main dictionary.
Dictionary items() is a method that returns a list of dictionary items.
The items() method produces a list of tuple pairs (Keys, Values) in the dictionary that were found by searching for them.
Python 2 Programming Demonstration
Dict = ‘Tim’ (18), ‘Charlie’ (12), ‘Tiffany’ (22) and ‘Robert’ (25).
“Students Name: percent s” will be printed. percent Dict.items()
Python 3 Demonstration
Dict = ‘Tim’ (18), ‘Charlie’ (12), ‘Tiffany’ (22) and ‘Robert’ (25).
print(“Students Name: percent s” percent list(Dict.items())) print(“Students Name: percent s” percent
For our Dict, we make use of the code items() method.
Upon execution of the code, the programme returns a list of elements (keys and values) from the dictionary.