LIST COMPREHENSION IN PYTHON

Creating the list object by writing business logic is known as “List Comprehension”.

Example –

a=[x for x in range(10)]
print a
y=[x**x for x in range(5)]
print y
i=[x for x in range(0,10,2)]
print i
j=[x*x for x in range(0,10,2)]
print j
k=[x for x in a if x%2==0]
print k

Output –

[0, 1, 2, 3, 4, 5, 6, 7, 8, 9]

[1, 1, 4, 27, 256]

[0, 2, 4, 6, 8]

[0, 4, 16, 36, 64]

[0, 2, 4, 6, 8]

Example –

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

Output –

[2, 3, 5, 7, 11, 13, 17, 19, 23, 29, 31, 37, 41, 43, 47]

Example –

line='the quick brown for jumps over the lazy dog'
words=line.split()
print words
stuff=[[w.upper(),w.lower(),len(w)]for w in words]
for i in stuff:
    print i

Output –

['the', 'quick', 'brown', 'for', 'jumps', 'over', 'the', 'lazy', 'dog']

['THE', 'the', 3]

['QUICK', 'quick', 5]

['BROWN', 'brown', 5]

['FOR', 'for', 3]

['JUMPS', 'jumps', 5]

['OVER', 'over', 4]

['THE', 'the', 3]

['LAZY', 'lazy', 4]

['DOG', 'dog', 3]