Render the Polynomial Filter

PandasHardSenior level~10 min

Problem

A signal-processing tool stores a polynomial as pieces in a DataFrame `polynomial_pieces` (loaded from a CSV) with columns `(degree, coefficient)`. `degree` is a unique non-negative integer; `coefficient` is an integer that may be positive or negative. Render the whole polynomial as one string `formula` of the form `<sign><coeff><var-part><sign><coeff><var-part>...=0`.

Rules:
- Pieces appear in descending order of `degree`.
- The variable is `n`. For `degree` 0 the piece has no variable part (`<sign><coeff>`). For `degree` 1 it is `<sign><coeff>n`. For higher degrees it is `<sign><coeff>n^<degree>`.
- Each coefficient is prefixed by its sign: `+` when positive; for negatives the `-` comes from the number itself.
- The whole string ends with `=0`.

Input data

Example rows — the live problem includes the full dataset.

polynomial_pieces

degree	coefficient
3	2
1	-5
0	7

Expected output

Your answer should return 1 row with the columns formula.

Starter code (Pandas (Python))

import pandas as pd

def render_the_polynomial_filter(polynomial_pieces) -> pd.DataFrame:
    # Your code here
    return polynomial_pieces

Solve this Pandas question free

Write Pandas (Python) and run it instantly in your browser — even on your phone. No signup needed to try.

Solve it now → Create free account

Solution & explanation

Create a free account to unlock the optimal solution, a step-by-step explanation, and the hidden test cases that grade your answer.