Python – Priority key assignment in dictionary

Python language is composed of various data structures and dictionary is one among them. The elements inside the dictionary data structure are separated by comma and provided inside the flower brackets that are “{}”. Python is popular worldwide because of its simplicity and flexibility with other applications. Apart from the other languages it has got its unique place because of its advantages like it’s easy to code with simple syntax and statement. The Dictionary data structure can hold large amount data set and finding the elements based on the priority would be difficult.

Priority key assignment in dictionary

Out of the various data structures in Python language, a dictionary is a complex one to handle the data structures. The dictionaries do not follow any orders of the elements and the key value assigned cannot be changed. The dictionary can hold the elements like lists, tuples or another dictionary. The basic syntax for the dictionary is, 

Dict_1 = {‘hello’: ‘all’, ‘welcome’: 897}

In this article, the way by which the elements can be sorted using the priority element is explained using different approaches.

Priority key assignment in python dictionaries allows developers to assign priorities to keys based on their importance. By assigning priorities to different keys within the dictionary, we can ensure that they get processed in a specific order regardless of their placement within the overall structure of the code.

Example of Priority Key assignment

Imagine having a fleet management system where each vehicle has multiple sensors attached that provide real-time updates about its condition like speed, fuel consumption and engine temperature. But if we use “priority_key” parameter while creating each sensor item (key) we have more control over dict processing order because elements with higher- value should be accessed first −

fleet_management = {'VehicleA': { 'EngineTemp': 45,'SpeedSensor': 65}, 
                    'VehicleB': { 'FuelConsumption' :34 ,'SpeedSensor' :80}}

In this case Vehicle A has EngineTemp with lower integer accepting high priority values while for Vehicle B Speed Sensor holds high-priority value over Fuel Consumption up as suggested by assigning higher integer value than 34.

Thus, by following such property every time we access fleets data in loop/iteration will produce results prioritized based on those “priority_keys” values which are much more useful when working with data of different priority levels.


  • Approach 1 − Using the matching element

  • Approach 2 − Using the iteration method

Approach 1: Python Program to print the priority key assignment in dictionary using the matching element

The generate expression is used to match the elements in the list and dictionary data structure.


  • Step 1 − The dictionary value is initialized with the string and key pairs.

  • Step 2 − The list data structure is declared with some more string elements.

  • Step 3 − The matching elements are found using the generator expression between the list and dictionary.

  • Step 4 − The element which is matching or priority is printed.

  • Step 5 − Then the final value is printed.


# Initialize a dictionary with some key-value pairs.
dict1 = {'Hello' : 9, 'to' : 6, 'Welcome' : 3, 'ALL' : 56}

# Initialize a list with some elements.
list1 = ['ALL', 'is', 'come']

# Get the matching element from list1 and dict1.
matching_element = next((a for a in list1 if a in dict1), None)

# Print the matching element.
print("Matching element is : " + str(matching_element))

# Print the value of matching_element.
print("Value of matching element is : " + str(dict1[matching_element]))


Matching element is : ALL
Value of matching element is : 56

Approach 2: Python Program to print the priority key assignment in dictionary using the iteration method

The dictionary data structure and the priority list are initialized and the priority key is returned when the elements are matched. When the element does not match, it returns none value.


  • Step 1 − The dictionary value is initialized with string values and a key value is assigned.

  • Step 2 − The Priority list follows the list data structure with some strings to match the values.

  • Step 3 − The variable is assigned a value as “None”.

  • Step 4 − The for loop is used to iterate through the given dictionary value.

  • Step 5 − When the current value is matched with the dictionary, then it returns the key value.


#initializing the dictionary data structure
dict1 = {'Hello' : 9, 'to' : 6, 'Welcome' : 3, 'ALL' : 56}
#Declaring the priority list to match it with the dictionary data structure
prioritylist = ['ALL', 'John', 'Home']

#Declaring val as None
val = None
#for loop will iterate through the dictionary of values
for num in dict1:
#If the element is present in both dict1 and prioritylist
	if num in prioritylist :
		val = dict1[num]
#Print function will return the priority element
print("Value of matching element is : " + str(val))


Value of matching element is : 56


In the current world, handling data is the most challenging task for organizations with a high volume of data and with the development of data science and machine learning it has become easier to access. Python is a versatile and high-level language that can be understood easily by the user.

Updated on: 04-Sep-2023


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