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Python: Sort a dictionary by key

Python dictionary: Exercise-14 with Solution

Write a Python program to sort a given dictionary by key

Sample Solution-1:

Python Code:

color_dict = {'red':'#FF0000',
          'green':'#008000',
          'black':'#000000',
          'white':'#FFFFFF'}

for key in sorted(color_dict):
    print("%s: %s" % (key, color_dict[key]))
	

Sample Output:

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

Visualize Python code execution:

The following tool visualize what the computer is doing step-by-step as it executes the said program:


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:

def sort_dict_by_key(d, reverse = False):
  return dict(sorted(d.items(), reverse = reverse))
students = { 'name1': 'Theodore', 'name2': 'Mathew', 'name4': 'Roxanne', 'name3': 'David' }
print("Original dictionary:")
print(students)
print("\nSort the said dictionary by key (Ascending order):")
print(sort_dict_by_key(students))
print("\nSort the said dictionary by key (Descending order):")
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:

Flowchart: Sort a dictionary by key

Visualize Python code execution:

The following tool visualize what the computer is doing step-by-step as it executes the said program:


Python Code Editor:

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Previous: Write a Python program to map two lists into a dictionary.
Next: Write a Python program to get the maximum and minimum value in a dictionary.

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Python: Tips of the Day

Decapitalizes the first letter of a string:

Example:

def tips_decapitalize(s, upper_rest=False):
  return s[:1].lower() + (s[1:].upper() if upper_rest else s[1:])
print(tips_decapitalize('PythonTips'))
print(tips_decapitalize('PythonTips', True)) 

Output:

pythonTips
pYTHONTIPS