CODEWITHSUNDEEP
python
Anshul Goyal
Anshul Goyal

Reputation: 139

Sorting list of dictionaries in python by day of week

I have a list of dicts in python which look like these:

[{'day' : 'Wednesday' , 'workers' : ['John' , 'Smith']} , 
 {'day' : 'Monday' , 'workers' : ['Kelly']}]

I want to sort them by day of week such that the result is

[{'day' : 'Monday' , 'workers' : ['Kelly']},
 {'day' : 'Wednesday' , 'workers' : ['John' , 'Smith']}]

I can use this answer to sort list of just weekday names: Sort week day texts but is there a way to sort the above dict?

Upvotes: 0

Views: 916

Answers (4)

Barmar
Barmar

Reputation: 781771

Use a lambda function that extracts the weekday name from the dictionary and then returns the index as in your linked question.

weekdays = ["Mon", "Tue", "Wed", "Thu", "Fri"]
list_of_dicts = 
    [{'day' : 'Wednesday' , 'workers' : ['John' , 'Smith']} , 
     {'day' : 'Monday' , 'workers' : ['Kelly']}]
list_of_dicts.sort(key = lambda d: weekdays.index(d['day']))

Upvotes: 2

pakpe
pakpe

Reputation: 5479

Here it is:

lst = [{'day' : 'Wednesday' , 'workers' : ['John' , 'Smith']} ,
       {'day' : 'Monday' , 'workers' : ['Kelly']},
       {'day' : 'Friday' , 'workers' : ['Nelly']}]

m = ["Monday", "Tuesday", "Wednesday", "Thursday", "Friday"]
result = sorted(lst, key= lambda x: m.index(x['day']))

print(result)
#[{'day': 'Monday', 'workers': ['Kelly']}, {'day': 'Wednesday', 'workers': ['John', 'Smith']}, {'day': 'Friday', 'workers': ['Nelly']}]

Upvotes: 0

Roy Cohen
Roy Cohen

Reputation: 1570

To sort a dictionary by a key "key", you can do:

sorted(dicts, key=lambda d: d["key"])

Merging this with the answer from the question you linked:

m = ["Monday", "Tuesday", ...]
print(sorted(dicts, key=lambda d: m.index(d["day"])))

Upvotes: 1

rhurwitz
rhurwitz

Reputation: 2747

The same basic approach that the example you link to uses will work for your list of dictionaries case. The trick is, you need to extract the day value from the dictionaries within the list to make it work. A lambda expression used for the key parameter is one way to do that.

Example:

day_order = ["Monday", "Tuesday", "Wednesday", "Thursday", "Friday"]
data = [{'day' : 'Wednesday' , 'workers' : ['John' , 'Smith']} , {'day' : 'Monday' , 'workers' : ['Kelly']}]

sorted(data, key=lambda d: day_order.index(d["day"]))

Output:

[{'day': 'Monday', 'workers': ['Kelly']},
 {'day': 'Wednesday', 'workers': ['John', 'Smith']}]

Upvotes: 4

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