Iterator Functions in Python | Set 1

# Python code to demonstrate the working of 
# accumulate() and chain()

# importing "itertools" for iterator operations
import itertools

# importing "operator" for operator operations
import operator

# initializing list 1
li1 = [1, 4, 5, 7]

# initializing list 2
li2 = [1, 6, 5, 9]

# initializing list 3
li3 = [8, 10, 5, 4]

# using accumulate()
# prints the successive summation of elements
print ("The sum after each iteration is : ",end="")
print (list(itertools.accumulate(li1)))

# using accumulate()
# prints the successive multiplication of elements
print ("The product after each iteration is : ",end="")
print (list(itertools.accumulate(li1,operator.mul)))

# using chain() to print all elements of lists
print ("All values in mentioned chain are : ",end="")
print (list(itertools.chain(li1,li2,li3)))

# Python code to demonstrate the working of 
# chain.from_iterable() and compress()

# importing "itertools" for iterator operations
import itertools

# initializing list 1
li1 = [1, 4, 5, 7]

# initializing list 2
li2 = [1, 6, 5, 9]

# initializing list 3
li3 = [8, 10, 5, 4]

# initializing list of list
li4 = [li1, li2, li3]

# using chain.from_iterable() to print all elements of lists
print ("All values in mentioned chain are : ",end="")
print (list(itertools.chain.from_iterable(li4)))

# using compress() selectively print data values
print ("The compressed values in string are : ",end="")
print (list(itertools.compress('GEEKSFORGEEKS',[1,0,0,0,0,1,0,0,1,0,0,0,0])))

# Python code to demonstrate the working of 
# dropwhile() and filterfalse()

# importing "itertools" for iterator operations
import itertools

# initializing list 
li = [2, 4, 5, 7, 8]

# using dropwhile() to start displaying after condition is false
print ("The values after condition returns false : ",end="")
print (list(itertools.dropwhile(lambda x : x%2==0,li)))

# using filterfalse() to print false values
print ("The values that return false to function are : ",end="")
print (list(itertools.filterfalse(lambda x : x%2==0,li)))