Python keyword arguments unpack and return dictionary

Question

I have a function definition as below and I am passing keyword arguments. How do I get to return a dictionary with the same name as the keyword arguments?

Manually I can do:

def generate_student_dict(first_name=None, last_name=None , birthday=None, gender =None):
    return {
        'first_name': first_name,
        'last_name': last_name,
        'birthday': birthday,
        'gender': gender
    }

But I don't want to do that. Is there any way that I can make this work without actually typing the dict?

 def generate_student_dict(self, first_name=None, last_name=None, birthday=None, gender=None):
     return # Packed value from keyword argument.

Initially I wanted to pass this return dict to Django's Model create method. @PadraicCunningham — Karan Kumar, Feb 05 '16 at 06:24

score 14 · Accepted Answer · edited May 23 '17 at 10:28

14

If that way is suitable for you, use kwargs (see Understanding kwargs in Python) as in code snippet below:

def generate_student_dict(self, **kwargs):            
     return kwargs

Otherwise, you can create a copy of params with built-in locals() at function start and return that copy:

def generate_student_dict(first_name=None, last_name=None , birthday=None, gender =None):
     # It's important to copy locals in first line of code (see @MuhammadTahir comment).
     args_passed = locals().copy()
     # some code
     return args_passed

generate_student_dict()

edited May 23 '17 at 10:28

Community

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answered Feb 04 '16 at 10:06

Andriy Ivaneyko

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locals() will only work if there is no variable defined in the body of the method :) – Muhammad Tahir Feb 04 '16 at 10:12
@MuhammadTahir Thanks for your correction, i've updated answer – Andriy Ivaneyko Feb 04 '16 at 10:13

score 7 · Answer 2 · answered Feb 04 '16 at 10:06

If you don't want to pass **kwargs, you can simply return locals:

def generate_student_dict(first_name=None, last_name=None, 
                          birthday=None, gender=None):
    return locals()

Note that you want to remove self from the result if you pass it as an argument.

Muhammad Tahir · Answer 3 · 2016-02-04T10:08:10.047

3

Get keyword arguments in **kwargs

def generate_student_dict(self, **kwargs):
  # use it like
  # kwargs.get('first_name')
  # kwargs.get('last_name')
  # kwargs.get('birthday')
  # kwargs.get('gender')
  return kwargs

edited Feb 04 '16 at 10:08

answered Feb 04 '16 at 10:05

Muhammad Tahir

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score 0 · Answer 4 · edited Feb 04 '16 at 10:30

0

You can use locals() function. locals() updates and returns a dictionary representing the current local symbol table. Free variables are returned by locals() when it is called in function blocks, but not in class blocks.

edited Feb 04 '16 at 10:30

Maroun

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answered Feb 04 '16 at 10:09

user2719152

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score -1 · Answer 5 · edited Feb 11 '20 at 12:40

In case you want to return the updated values as dictionary

    def generate_student_dict(first_name=None, last_name=None , birthday=None, gender =None):
        main_args = locals().copy()
        first_name = 'first'
        last_name = 'last'
        birthday = '20 jan 1993'
        newvar = 100
        new_args = locals().copy()
        updated_args = {}

        for k,v in new_args.items():
            if k in main_args.keys():
                updated_args[k] = v
        return updated_args

    dict = generate_student_dict()
    print(dict) #{'first_name': 'first', 'last_name': 'last', 'birthday': '20 jan 1993', 'gender': None}

In case you want to return the iniital values as dictionary

    def generate_student_dict_1(first_name=None, last_name=None , birthday=None, gender =None):
        args = locals()
        first_name = 'first'
        last_name = 'last'
        birthday = '20 jan 1993'
        newvar = 100
        return args

    dict = generate_student_dict_1()
    print(dict) #{'first_name': None, 'last_name': None, 'birthday': None, 'gender': None}

if you want to include all the changes including extra variables defined inside the method

    def generate_student_dict_2(first_name=None, last_name=None , birthday=None, gender =None):
        first_name = 'first'
        last_name = 'last'
        birthday = '20 jan 1993'
        newvar = 100
        args = locals()
        return args

    dict = generate_student_dict_2()
    print(dict) #{'first_name': 'first', 'last_name': 'last', 'birthday': '20 jan 1993', 'gender': None, 'newvar': 100}

Python keyword arguments unpack and return dictionary

5 Answers5