* usages, *args, **kwargs in Python

asterisk_usages.py

# The object after * must be a iterator
# * is used to unpack a iterator 
list_1 = [0,1,2]
print(list_1)
# Iterate  list
print(*list_1)

print("*"*50)

tuple_1 = (0,1,2)
print(tuple_1)
# Iterate the tuple
print(*tuple_1)

print("*"*50)

dict_1 = {"arg_0":0, "arg_1":1, "arg_2":2}
print(dict_1)
# Iterate the keys in the dictionary
print(*dict_1)
# Get the keys in the dictionary as list
print([*dict_1])

print("*"*50)

def gen_func(n):
    for i in range(n):
        yield i
# Generator is also an iterator
gen_1 = gen_func(3)
print(gen_1)
# Iterate the generator
print(*gen_1)

print("*"*50)

# *args in Python
# You would be very limited by this variable number of arguments
# Keyword name would not be supported anymore
def func_1(arg_0, arg_1=1000, *args):
    print(arg_0)
    print(arg_1)
    print(args)
    print(type(args))

func_1(0, 1, 2, 3)
# Illegal function calls if keyword is used
# func_1(arg_0=0, arg_1=1, arg_2=2)
# func_1(arg_0=0, 1, 2)
# func_1(0, 1, arg_0=2)

print("*"*50)

# **kwargs in Python
def func_2(arg_0, arg_1=1000, **kwargs):
    print(arg_0)
    print(arg_1)
    print(kwargs)
    print(type(kwargs))

func_2(0, lion=10000)
print("-"*50)
func_2(0, 1, lion=10000)
print("-"*50)
func_2(0, 1, lion=10000, panda=20000)
# Illegal function calls
# func_2(0, 1, 2, lion=10000)

print("*"*50)

# Use *args and **kwargs together
def func_3(arg_0, arg_1=1000, *args, **kwargs):
    print(arg_0)
    print(arg_1)
    print(args)
    print(kwargs)

func_3(0)
print("-"*50)
func_3(0, 1)
print("-"*50)
func_3(0, 1, 2)
print("-"*50)
func_3(0, lion=10000)
print("-"*50)
func_3(0, 1, lion=10000)
print("-"*50)
func_3(0, 1, 2, lion=10000)
print("-"*50)
func_3(arg_0=0, lion=10000)
print("-"*50)
func_3(arg_0=0, arg_1=1, lion=10000)
print("-"*50)
func_3(arg_0=0, arg_1=1, arg_2=2, lion=10000)
print("-"*50)
func_3(0, lion=10000)
print("-"*50)
func_3(0, 1, arg_2=2, lion=10000)
print("-"*50)
func_3(0, 1, 2, arg_2=2, lion=10000)

print("*"*50)

# Make good use of **kwargs
def func_4(arg_0, arg_1=1000, *args, **kwargs):
    print(arg_0)
    if "panda" in kwargs:
        print(kwargs["panda"])

func_4(0, panda=20000)
print("-"*50)
func_4(0, elephant=30000)

print("*"*50)

# Some corner usages of *
first, *middle, last = [1,2,3,4]
print(middle)
print(type(middle))