definition also allows for some interesting and useful iterator functions to efficiently loop and speed up code execution. The itertools module has many built-in iterators.
This module implements a number of iterator building blocks.
Some useful iterators:
1. accumulate (iter, func) : — this iterator takes two arguments, an iterative target and a function to follow at each iteration of the value in the target . If no function is passed, append is the default. If the input iteration is empty, the output iteration will also be empty.
2. chain (iter1, iter2 ..) : — This function is used to output all values for iterable purposes one by one mentioned in its arguments.
# Python code for demonstration works
# accumulate () and chain ()
# import & quot; itertools & quot; for iterator operations import itertools
# import & quot; operator & quot; for operator operations import operator
# initializing list 1 li1 = [ 1 , 4 , 5 , 7 ]
# initializing list 2 li2 = [ 1 , 6 , 5 , 9 ]
# initialization list 3 li3 = [ 8 , 10 , 5 , 4 ]
# using accumulation ()
# prints a sequential sum of elements print ( "The sum after each iteration is:" , end = " ") print ( list (itertools.accumulate (li1)))
# using accumulation ()
# prints sequential multiplication of elements print ( " The product after each iteration is: " , end = " ") print ( list (itertools.accumulate (li1, operator.mul)))
# using chain () to print all list items print ( "All values in the mentioned chain are:" , end = "") prin t ( list (itertools.chain (li1, li2, li3) ))
Output:
The sum after each iteration is: [1, 5, 10, 17] The product after each iteration is: [1, 4, 20, 140] All values in the mentioned chain are: [1, 4, 5, 7, 1, 6 , 5, 9, 8, 10, 5, 4]
3. chain.from_iterable () : — this function is implemented similarly to chain (), but the argument here is a list of lists or any other iterable .
4. compress (iter, selector) : — this iterator selectively selects the values to print from the given container according to the boolean list value passed as another argument. Arguments matching the boolean true are printed, otherwise all are skipped.
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Output:
All values in mentioned chain are: [1, 4, 5 , 7, 1, 6, 5, 9, 8, 10, 5, 4] The compressed values in string are: ['G',' F', 'G']
5 ... dropwise (func, seq) : — This iterator starts printing only characters after the function. in argument returns false the first time.
6. filterfalse (func, seq) : — As the name suggests, this iterator only prints values that return false for the passed function.
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