145

My code

1st file:

data = {'school':'DAV', 'standard': '7', 'name': 'abc', 'city': 'delhi'}
my_function(*data)

2nd file:

my_function(*data):
    schoolname  = school
    cityname = city
    standard = standard
    studentname = name

in the above code, only keys of "data" dictionary were get passed to my_function(), but i want key-value pairs to pass. How to correct this ?

I want the my_function() to get modified like this

my_function(school='DAV', standard='7', name='abc', city='delhi')

and this is my requirement, give answers according to this

EDIT: dictionary key class is changed to standard

3
  • 9
    Don't use variable names that are default objects in Python, such as the word class.
    – Torxed
    Commented Feb 24, 2014 at 11:19
  • 3
    ...and this is my requirement, give answers according to this -- Ugh, a bit harsh. But a good question, nonetheless.
    – pfabri
    Commented May 22, 2020 at 15:46
  • 4
    @pfabri, it's quite clear from reading the question that English is not user's native language, so it's very possible that the harshness was unintended and that's just how they translated it to English.
    – stason
    Commented Sep 17, 2020 at 6:28

3 Answers 3

265

If you want to use them like that, define the function with the variable names as normal:

def my_function(school, standard, city, name):
    schoolName  = school
    cityName = city
    standardName = standard
    studentName = name

Now you can use ** when you call the function:

data = {'school':'DAV', 'standard': '7', 'name': 'abc', 'city': 'delhi'}

my_function(**data)

and it will work as you want.

P.S. Don't use reserved words such as class.(e.g., use klass instead)

10
  • i have this line def my_function(*data), modify your code according to this line
    – Patrick
    Commented Feb 24, 2014 at 12:03
  • 3
    you mean to recompile whole python interpreter to work like you want it to work?
    – markcial
    Commented Feb 24, 2014 at 12:06
  • 1
    @markcial is there any way to implement in code as i like ?
    – Patrick
    Commented Feb 24, 2014 at 13:08
  • @Patrick Not a chance, the only way is the one that RemcoGerlih proposed. He has a working sample of code, yours has failed, then is logical to follow their guidelines
    – markcial
    Commented Feb 24, 2014 at 13:09
  • 1
    @MayankChoudhary: either first construct a new dictionary with only the selected keys and pass it with **, or just do my_function(mykey1=mydict["mykey1"], ...). There is no automatic way to call a function like that. Commented Mar 1, 2017 at 10:42
69

*data interprets arguments as tuples, instead you have to pass **data which interprets the arguments as dictionary.

data = {'school':'DAV', 'class': '7', 'name': 'abc', 'city': 'pune'}


def my_function(**data):
    schoolname  = data['school']
    cityname = data['city']
    standard = data['class']
    studentname = data['name']

You can call the function like this:

my_function(**data)
0
18

You can just pass it

def my_function(my_data):
    my_data["schoolname"] = "something"
    print my_data

or if you really want to

def my_function(**kwargs):
    kwargs["schoolname"] = "something"
    print kwargs
2
  • made my day :-) Commented Nov 25, 2017 at 11:22
  • 15
    There is a fundamental difference between the two. The first passes a reference the second copies the data. If you pass a reference and the dictionary gets changed inside the function it will be changed outside the function as well which can cause very bad side effects. Commented Feb 25, 2020 at 6:24

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