itertools.islice

itertools.islice(itr,start=None,stop,step=1)

• The islice function is used to:

  • Cycle through each element of an iterable
  • Select a slice of elements from the iterable
  • This slice follows a step-pattern determined by step
• This iterable is based on the itr parameter
• This slice is between the start and stop indices

• The start parameter is optional

  • It defaults to the first element of the iterable

• The step parameter is optional as well

  • It defaults to $1$
• islice returns an iterator of every step$^{th}$ element within the slice made up by start and stop

Illustrating the islice Function

>>> from itertools import islice
>>> letters = 'abcde'

>>> slice = islice(letters, 2)
>>> for i in slice: print(i)
'a'
'b'

>>> slice = islice(letters, 2, 4)
>>> for i in slice: print(i)
'c'
'd'

>>> slice = islice(letters, 2, None)
>>> for i in slice: print(i)
'c'
'd'
'e'

>>> slice = islice(letters, 0, None, 2)
>>> for i in slice: print(i)
'a'
'c'
'e'

References

• Documentation of the Islice Function from Itertools