过滤掉特定的衍生物

Question

I have generated several functions.

find_derivative simply takes the derivative of several terms using the product rule and makes a new equation.

So if i input 3x^2 + 2x^3

I get 6x + 6x^2

in the output [(6,1),(6,2)]

However I want to filter out any time I end up with an output with a tuple that begins with 0

def find_derivative(function_terms):
    new_function = []
    for term in function_terms:
        new_term = find_term_derivative(term)
        new_function.append(new_term)
        filtered_list = list(filter(lambda x: x != 0, new_function))
    return filtered_list

The expected result from input [(3, 2), (-11, 0)] should be [(6, 1)] but this code is not removing the second term, [0,-1]

EDIT: derivative function

def find_term_derivative(term): 
    x, y = term
    new_term = (x*y, y-1)
    return new_term 

Answer 1

You have the right idea with the filter, but take a look at the lambda you've written. You're filtering on the condition lambda x : x != 0 , which will check if the element in the list is not zero.

But the elements in your list are tuples, and you want to check if only the first number in the tuple is zero, so you need to update your condition to be lambda x : x[0] != 0 .