Can I pass variable values with named and each set is optionally

Question

I want my function can be called by this way,

And the order of parameters is insensitive.

The two functions identical

search(categories=["oll","Academic Data"], names=["mary","jack"])

search(names=["mary","jack"], categories=["oll","Academic Data"])

I can also pass that way

search(names=["mary","jack"])

Finally, I hope i can get the parameters into an dictionary.

I want the parameters to be explicit but rather than dictionary Thanks

SO you want to call a user-defined function `search` which takes a minimum one argument names and produces a dictionary as output — The6thSense, Jul 08 '15 at 06:14

score 2 · Answer 1 · answered Jul 08 '15 at 06:14

Have you tried:

def search(names = [], categories = []):
     print(names)
     print(categories)

>>> search(names=["mary","jack"])
['mary', 'jack']
[]
>>> search(categories=["oll","Academic Data"], names=["mary","jack"])
['mary', 'jack']
['oll', 'Academic Data']

If you do not want the 'names' arg to be optional, just remove the default [] in function args.

Anand S Kumar · Answer 2 · 2015-07-08T07:35:24.333

You can define the function as -

def foo(**kwargs):
    print(kwargs)

This will allow named parameters to be passed in, and kwargs would be a dictionary of those named parameters -

>>> foo(categories=["oll","Academic Data"], names=["mary","jack"])
{'categories': ['oll', 'Academic Data'], 'names': ['mary', 'jack']}
>>> foo(names=["mary","jack"], categories=["oll","Academic Data"])
{'categories': ['oll', 'Academic Data'], 'names': ['mary', 'jack']}
>>> foo(names=["mary","jack"])

Or another option (if you want to be explicit about the parameters) is to set a default value for the parameters, when using named arguments, they can be in any order, exmaple -

>>> def foo1(categories=None,names=None):
...     print('categories - ' + str(categories))
...     print('names - ' + str(names))
...
>>> foo1(categories=["oll","Academic Data"], names=["mary","jack"])
categories - ['oll', 'Academic Data']
names - ['mary', 'jack']
>>> foo1(names=["mary","jack"], categories=["oll","Academic Data"])
categories - ['oll', 'Academic Data']
names - ['mary', 'jack']
>>> foo1(names=["mary","jack"])
categories - []
names - ['mary', 'jack']

Even without default values, when you are using named arguments in function calling, the order of the arguments do not matter, they only matter when you do not specify the names of the arguments when calling the function). Example -

>>> def func(a, b):
...     print(a, b)
...
>>> func(b=1,a=2)
2 1
>>> func(a=2,b=1)
2 1

Adding default value for the argument, makes them optional during calling.

@jonrsharpe Do you mean we should be careful about that when using default values for arguments? — Anand S Kumar, Jul 08 '15 at 07:29

The6thSense · Answer 3 · 2015-07-08T07:39:47.110

1

def search(names, categories = None):
    if categories:
        return ({"name":names,"categories":categories})
    return ({"name":names})

Output:

search(names=["mary","jack"])
{'name': ['mary', 'jack']}

search(names=["mary","jack"],categories=["man"])
{'categories': ['man'], 'name': ['mary', 'jack']}

If you want to provide a optional variable provide it's type when defining i.e.)categories = [] if you want a permanent argument don't define it's type i.e.)names

edited Jul 08 '15 at 07:39

answered Jul 08 '15 at 06:19

The6thSense

8,103
8
31
65

@jonrsharpe I understand what you are trying to say but can you give me a condition where this might fail and a remedy for that – The6thSense Jul 08 '15 at 07:36
Have you *read* the question and its answers? They cover that pretty well. – jonrsharpe Jul 08 '15 at 07:37
@jonrsharpe as per my understanding from reading the question and answer it is harfull only when it is called from other function – The6thSense Jul 08 '15 at 07:42

score 0 · Answer 4 · answered Jul 08 '15 at 06:15

Looking for this?

def search(**kwargs):
    print(kwargs)

search(categories=["oll","Academic Data"], names=["mary","jack"])
search(names=["mary","jack"], categories=["oll","Academic Data"])
search(names=["mary","jack"])

Prints:

{'names': ['mary', 'jack'], 'categories': ['oll', 'Academic Data']}
{'names': ['mary', 'jack'], 'categories': ['oll', 'Academic Data']}
{'names': ['mary', 'jack']}

Can I pass variable values with named and each set is optionally

4 Answers4