Python: Sort a dictionary by key

Last update on December 21 2024 07:28:11 (UTC/GMT +8 hours)

Write a Python program to sort a given dictionary by key

Sample Solution-1:

Python Code:

# Create a dictionary 'color_dict' with color names as keys and their corresponding color codes in hexadecimal format as values.
color_dict = {
    'red': '#FF0000',
    'green': '#008000',
    'black': '#000000',
    'white': '#FFFFFF'
}

# Iterate through the keys of the 'color_dict' dictionary after sorting them in lexicographical order.
for key in sorted(color_dict):
    # Print each key-value pair where '%s' is a placeholder for the key and its associated color code.
    print("%s: %s" % (key, color_dict[key]))
	

Sample Output:

black: #000000                                                                                                
green: #008000                                                                                                
red: #FF0000                                                                                                  
white: #FFFFFF 

Sample Solution-2:

• Use dict.items() to get a list of tuple pairs from d and sort it using sorted().
• Use dict() to convert the sorted list back to a dictionary.
• Use the reverse parameter in sorted() to sort the dictionary in reverse order, based on the second argument.

Python Code:

# Define a function 'sort_dict_by_key' that takes a dictionary 'd' and an optional 'reverse' flag.
# It returns the dictionary 'd' sorted by keys in ascending or descending order, based on the 'reverse' flag.
def sort_dict_by_key(d, reverse = False):
    # Use the 'sorted' function to sort the items (key-value pairs) in the dictionary 'd' by their keys.
    # The 'reverse' flag is used to specify the sorting order.
    return dict(sorted(d.items(), reverse=reverse))

# Create a dictionary 'students' with keys representing names and corresponding values.
students = { 'name1': 'Theodore', 'name2': 'Mathew', 'name4': 'Roxanne', 'name3': 'David' }

# Print a message indicating the start of the code section.
print("Original dictionary:")

# Print the original dictionary 'students'.
print(students)

# Print a message indicating the start of sorting the dictionary by key in ascending order.
print("\nSort the said dictionary by key (Ascending order):")

# Call the 'sort_dict_by_key' function to sort the 'students' dictionary by key in ascending order.
# Print the result, which is the sorted dictionary.
print(sort_dict_by_key(students))

# Print a message indicating the start of sorting the dictionary by key in descending order.
print("\nSort the said dictionary by key (Descending order):")

# Call the 'sort_dict_by_key' function with 'reverse=True' to sort the 'students' dictionary by key in descending order.
# Print the result, which is the sorted dictionary in descending order by key.
print(sort_dict_by_key(students, True)) 

Sample Output:

Original dictionary:
{'name1': 'Theodore', 'name2': 'Mathew', 'name4': 'Roxanne', 'name3': 'David'}

Sort the said dictionary by key (Ascending order):
{'name1': 'Theodore', 'name2': 'Mathew', 'name3': 'David', 'name4': 'Roxanne'}

Sort the said dictionary by key (Descending order):
{'name4': 'Roxanne', 'name3': 'David', 'name2': 'Mathew', 'name1': 'Theodore'}

Flowchart:

Python Code Editor:

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