Infinite Iterators in Python
Iterator in Python is any python type that can be used with a ‘for in loop
’. Python lists, tuples, dictionaries, and sets are all examples of inbuilt iterators. But it is not necessary that an iterator object has to exhaust, sometimes it can be infinite. Such type of iterators are known as Infinite iterators.
Python provides three types of infinite iterators –
- count(start, step): This iterator starts printing from the “start” number and prints infinitely. If steps are mentioned, the numbers are skipped else step is 1 by default. See the below example for its use with
for in
loop.
Example:
import itertools
for i in itertools.count( 5 , 5 ):
if i = = 35 :
break
else :
print (i, end = " " )
|
Output:
5 10 15 20 25 30
- cycle(iterable): This iterator prints all values in order from the passed container. It restarts printing from beginning again when all elements are printed in a cyclic manner.
Example #1:
import itertools
count = 0
for i in itertools.cycle( 'AB' ):
if count > 7 :
break
else :
print (i, end = " " )
count + = 1
|
Output:
A B A B A B A B
Example #2: Using next function.
import itertools
l = [ 'Geeks' , 'for' , 'Geeks' ]
iterators = itertools.cycle(l)
for i in range ( 6 ):
print ( next (iterators), end = " " )
|
Output:
Geeks for Geeks Geeks for Geeks
- repeat(val, num): This iterator repeatedly prints the passed value infinite number of times. If the optional keyword
num
is mentioned, then it repeatedly prints num
number of times.
Example:
import itertools
print ( "Printing the numbers repeatedly : " )
print ( list (itertools.repeat( 25 , 4 )))
|
Output:
Printing the numbers repeatedly :
[25, 25, 25, 25]
Last Updated :
06 Dec, 2019
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