intersection of llist in python 3.9 code example

Example 1: python list comprehension

#example: removing common elements found in `a` from `b`.
a = [1,2,3,4,5]
b = [5,6,7,8,9]
# desired output: [1,2,3,4]

# gets each item found in `a` AND not in `b`
print([i for i in a if i not in b])

Example 2: Python dictionary append

# to add key-value pairs to a dictionary:

d1 = {
	"1" : 1,
	"2" : 2,
  	"3" : 3
} # Define the dictionary

d1["4"] = 4 # Add key-value pair "4" is key and 4 is value

print(d1) # will return updated dictionary