Components of List comprehensions :-
1. An Input Sequence - From which new sequence is built
2. A variable representing members of the input sequence.
3. An conditional expression [ Optional ]
4. An output expression producing elements of the output list - all elements of input sequence which satisfies conditional expression, if available.
1. Use a list comprehension print even numbers from 0 to n(n is some arbitrary value).
>>> values = [x for x in range(0, n+1) if x%2==0] >>> values [0, 2, 4]Here range(0, n+1) is input sequence, x is variable representing members of the input sequence, if x%2==0 represents conditional expression and x at beginning generates output sequence.
2. Using list comprehension print the Fibonacci Sequence in comma separated form for given input n.
def f(n): if n == 0: return 0 elif n == 1: return 1 else: return f(n-1)+f(n-2) n=int(raw_input()) values = [str(f(x)) for x in range(0, n+1)] print ",".join(values)O/P:- 4
Here str(f(x)) (converting int to string) generates output sequence as list.
3.Using list comprehension, write a program to print the list after removing the 0th, 2nd, 4th , 6th elements in [2,14,45,19,18,10,55].
li = [12,24,35,70,88,120,155] li = [x for (i,x) in enumerate(li) if i%2!=0] print liO/P:- [24, 70, 120]
4. Using list comprehension, write a program to print the list with numbers which are divisible by 5 and 7 in [12,24,35,70,88,120,155]
>>> li =[12,24,35,70,88,120,155] >>> li = [x for x in li if x%5 ==0 and x%7 ==0] >>> li [35, 70]
Note:- Python 3.0 supports Set and Dict comprehensions too.