In Python, you can use generator expressions to filter elements from an iterable and sum them up. A generator expression is similar to a list comprehension, but it returns a generator object instead of a list.

Here's an example that demonstrates how to filter and sum up elements using a generator expression:

numbers = [1, 2, 3, 4, 5, 6, 7, 8, 9, 10]
 
# create a generator expression to filter even numbers
even_numbers = (num for num in numbers if num % 2 == 0)
 
# sum up the even numbers using the sum() function
even_sum = sum(even_numbers)
 
print(even_sum)
# Output: 30

In this example, we have a list of numbers from 1 to 10. We create a generator expression called even_numbers that filters out only the even numbers from the original list. The condition if num % 2 == 0 filters out any elements that are not even.

We then use the built-in sum() function to sum up the even numbers generated by even_numbers. The result is stored in the variable even_sum.

You can use this technique to filter and sum up elements from any iterable, including files and databases. For example, to filter and sum up numbers from a file, you can use the following code:

# open a file containing numbers
with open('numbers.txt', 'r') as f:
    # create a generator expression to filter even numbers
    even_numbers = (int(line.strip()) for line in f if int(line) % 2 == 0)
 
    # sum up the even numbers using the sum() function
    even_sum = sum(even_numbers)
 
print(even_sum)

This code opens a file called numbers.txt, reads each line, and filters out only the even numbers using a generator expression. The even numbers are then summed up using the sum() function.