Python Tricks #9 - Python List Comprehension

# Python program to demonstrate list comprehension in Python 

# below list contains square of all odd numbers from 
# range 1 to 10 
odd_square = [x ** 2 for x in range(1, 11) if x % 2 == 1] 
print odd_square 

# for understanding, above generation is same as, 
odd_square = [] 
for x in range(1, 11): 
    if x % 2 == 1: 
        odd_square.append(x**2) 
print odd_square 

# below list contains power of 2 from 1 to 8 
power_of_2 = [2 ** x for x in range(1, 9)] 
print power_of_2 

# below list contains prime and non-prime in range 1 to 50 
noprimes = [j for i in range(2, 8) for j in range(i*2, 50, i)] 
primes = [x for x in range(2, 50) if x not in noprimes] 
print primes 

# list for lowering the characters 
print [x.lower() for x in ["A","B","C"]] 

# list which extracts number 
string = "my phone number is : 11122 !!"

print("\nExtracted digits") 
numbers = [x for x in string if x.isdigit()] 
print numbers 

# A list of list for multiplication table 
a = 5
table = [[a, b, a * b] for b in range(1, 11)] 

print("\nMultiplication Table") 
for i in table: 
    print i