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:
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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
Find current directory and file's directory:
To get the full path to the directory a Python file is contained in, write this in that file:
import os dir_path = os.path.dirname(os.path.realpath(__file__))
(Note that the incantation above won't work if you've already used os.chdir() to change your current working directory, since the value of the __file__ constant is relative to the current working directory and is not changed by an os.chdir() call.)
To get the current working directory use
import os cwd = os.getcwd()
Documentation references for the modules, constants and functions used above:
- The os and os.path modules.
- The __file__ constant
- os.path.realpath(path) (returns "the canonical path of the specified filename, eliminating any symbolic links encountered in the path")
- os.path.dirname(path) (returns "the directory name of pathname path")
- os.getcwd() (returns "a string representing the current working directory")
- os.chdir(path) ("change the current working directory to path")
Ref: https://bit.ly/3fy0R6m
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