Itertools Module:
Itertools is a Python module that contains a collection of functions for dealing with iterators. They make it very simple to iterate through iterables such as lists and strings.
Itertools.starmap() Function:
When an iterable is contained within another iterable and a function must be applied to both of them, starmap() is used. Each element of an iterable within another iterable is treated as a separate item by starmap(). It is comparable to a map (). This function belongs to the category of terminating iterators.
A built-in function, a user-defined function, or even a lambda function can be used.
Syntax:
starmap(function, iterable)
Parameters
function: This is Required. Procedures to be executed on iterable data.
iterable: This is Required. Elements that will be passed to the function.
Examples:
Example1:
Input:
Given List = [(6, 2), (5, 5), (2, 9), (7, 1), (0, 3)] function: lambda a, b: a + b
Output:
[8, 10, 11, 8, 3]
Example2:
Input:
Given List = [(6, 2), (5, 5), (2, 9), (7, 1), (0, 3)] function: lambda a, b: a * b
Output:
[12, 25, 18, 7, 0]
Itertools.starmap() Function with Examples in Python
Method #1: Using Built-in Functions (Static Input)
1)Using Lambda Function
Approach:
- Import starmap() function from itertools using the import keyword.
- Give the list as static input and store it in a variable.
- Pass lambda() function and given list as the arguments to the starmap() function where lambda() function adds the two numbers and store it in another variable.
- Convert the above result into a list using the list() function and store it in another variable.
- Print the above result.
- The Exit of the Program.
Below is the implementation:
# Import starmap() function from itertools using the import keyword. from itertools import starmap # Give the list as static input and store it in a variable. gvn_lst = [(6, 2), (5, 5), (2, 9), (7, 1), (0, 3)] # Pass lambda() function and given list as the arguments to the starmap() function # where lambda() function adds the two numbers and store it in another variable. rslt = starmap(lambda a, b: a + b, gvn_lst) # Convert the above result into a list using the list() function and store it in # another variable. rslt_lst = list(rslt) # Print the above result. print(rslt_lst)
Output:
[8, 10, 11, 8, 3]
2)Function Using def
Approach:
- Import starmap() function from itertools using the import keyword.
- Create a function say Multiplication which accepts three numbers as arguments and returns the multiplication of three numbers.
- Inside the function, Return multiplication of given three arguments.
- Give the list as static input and store it in a variable.
- Pass the above function(Multiplication) and given list as the arguments to the starmap() function where Multiplication() function multiplies the three numbers and store it in another variable.
- Convert the above result into a list using the list() function and store it in another variable.
- Print the above result.
- The Exit of the Program.
Below is the implementation:
# Import starmap() function from itertools using the import keyword.
from itertools import starmap
# Create a function say Multiplication which accepts three numbers as arguments and
# returns the multiplication of three numbers
def Multiplication(p, q, r):
# Return multiplication of given three arguments
return p*q*r
# Give the list as static input and store it in a variable.
gvn_lst = [(2, 5, 4), (1, 10, 2), (3, 5, 2)]
# Pass the above function(Multiplication) and given list as the arguments to the
# starmap() function where Multiplication() function multiplies the three numbers
# and store it in another variable.
rslt = starmap(Multiplication, gvn_lst)
# Convert the above result into a list using the list() function and store it in
# another variable.
rslt_lst = list(rslt)
# Print the above result.
print(rslt_lst)
Output:
[40, 20, 30]