PYTHON

python unpacking

"""Pythonic Unpacking
"""
## Unpacking iterables
lst = [1, 2, 3]
a, b, c = lst
print(a, b, c)
# a = 1, b = 2, c = 3

## The use of * for unpacking iterables
v, *end = [1, 2, 3, 4]
print(v, end)
# v = 1, end = [2, 3, 4]

v, *middle, z = [1, 2, 3, 4]
print(v, middle, z)
# v = 1, middle = [2, 3], z = 4

*v, end = [1, 2, 3, 4]
print(v, end)
# v = [1, 2, 3], end = 4


"""Try out other iterables to unpack!"""

python Unpacking

# unpacking values for even numbers in list comprehension
x, y, z = (i*i+i for i in range(6) if i%2==0)
x, y, z

unpacking in python

#When we create a tuple, we normally assign values to it. 
#This is called "packing" a tuple:

#Packing a tuple:
fruits = ("apple", "banana", "cherry")

#But, in Python, we are also allowed to extract the values back into variables.
#This is called "unpacking":

#Unpacking a tuple:
fruits = ("apple", "banana", "cherry")

(green, yellow, red) = fruits

print(green)
print(yellow)
print(red)

how to unpack in python

p = (4, 5)
x, y = p # x = 4, y = 5 

data = ['ACME', 50, 90.1, (2012, 12, 21)]
name, shares, price, date = data # name = ACME, shares = 50, price = 90.1, date = (2012, 12, 21)

say = "Big"
a, b, c = say # a = B, b = i, c = g

unpacking in python

# List Unpacking using *args
def count_sevens(*args):
    return args.count(7)

nums = [90,1,35,67,89,20,3,1,2,3,4,5,6,9,34,46,57,
       68,79,12,23,34,55,1,90,54,34,76,8,23,34,45,
       56,67,78,12,23,34,45,56,67,768,23,4,5,6,7,
        8,9,12,34,14,15,16,17,11,7,11,8,4,6,2,5,8,7,10,12,
        13,14,15,7,8,7,7,345,23,34,45,56,67,1,7,3,
        6,7,2,3,4,5,6,7,8,9,8,7,6,5,4,2,1,2,3,4,5,6,
        7,8,9,0,9,8,7,8,7,6,5,4,3,2,1,7]

print(count_sevens(*[1,4,7]) # 1 
print(count_sevens(*nums)) # 14 

# Dictionary Unpacking using **kwargs
def add_and_multiply_numbers(a,b,c):
    print(a + b * c)

data = dict(a=1, b=2, c=3)
      
add_and_multiply_numbers(**data) # 7