Deep Dive into Understanding Functions in Python
Awantik Das
Please note: All the code are executed in Python 2.7.
1. Function definition taking two arguments & returning one
def fun(arg1,arg2):
return arg1 + ' ' + arg2
fun("Hello","World")
OUTPUT>> Hello World
2. Function definition with Default Arguments
def default_fun( name, location = 'Bangalore'):
print name, location
default_fun('zekelabs', 'Mumbai')
OUTPUT>> zekelabs Mumbai
default_fun('zekelabs')
OUTPUT>> zekelabs Bangalore
PS: Default arguments can be only at end of function definition. No non-default arguments can be after default arguments
3. Function definition with keyword-based arguments
def keyword_func( name, location, gender ):
print name, location, gender
keyword_func(location='Bangalore', name='Jill', gender='male')
PS: Order of arguments in a function call doesn't matter. This is very useful with large number of function arguments
OUTPUT>> Jill Bangalore male
5. Function definition for variable arguments - accepting argument as a tuple
def varargs_func( *args ):
for arg in args:
print arg, # This will print all the arguments passed to the function
varargs_func('Jack','Jill','went', 'to','Malabar','hill')
OUTPUT>> Jack Jill went to Malabar hill
varargs_func('Raja', 'and', 'Rancho')
OUTPUT>> Raja and Rancho
6. Function definition for unpacking - passing list/tuple as argument
def unpacking_args_func(name,location,gender): print name,location,gender
info = ['Zekelabs','Bangalore','male'] unpacking_args_func( *info ) #passing list
OUTPUT>>Zekelabs Bangalore male
7. Function definition for accepting key-value pair as a dictionary. You will see lot of use cases in Python frameworks code like Django
def kwargs_func(**kwargs): #kwargs is a dictionary. We can fetch data by kwargs['key'] as well for k,v in kwargs.items(): print 'Key ',k, ' : ','Value ',v
kwargs_func(name='Zekelabs',location='Bangalore',price=1000)
OUTPUT>>
Key price : Value 1000
Key name : Value Zekelabs
Key location : Value Bangalore
8. Function definition for unpacking when a dictionary is passed.
Pass a dictionary and make sure all keys are arguments in function
def kwargs_unpack_func(name,location,price): print name,location,price
kwargs = {'name':'Awantik','location':'Bangalore','price':2000}
kwargs_unpack_func(**kwargs)
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