#0220

Zigzag String Rows

MediumPython25 min20 XP

Problem

Place characters into num_rows in zigzag movement and return the rows as a list of strings.

Why This Matters

This is a practical simulation pattern: keep row state and direction instead of trying to derive every index formula at once.

Function Signature

def zigzag_rows(text, num_rows):

Examples

Example 1

Inputtext = "PAYPAL", num_rows = 3

Output["PA", "APL", "Y"]

Characters move down rows 0,1,2 and then back up row 1.

Constraints

Return the exact requested value.
Handle small edge cases cleanly.
Prefer readable Python over clever shortcuts.

CodePython

def zigzag_rows(text, num_rows):
    """
    Input example: text = "PAYPAL", num_rows = 3
    Return: ["PA", "APL", "Y"]
    Return the value from the function so the tests can compare it. Do not print unless the prompt asks.
    """
    # write your code here
    return []

def zigzag_rows(text, num_rows):
    """
    Input example: text = "PAYPAL", num_rows = 3
    Return: ["PA", "APL", "Y"]
    Return the value from the function so the tests can compare it. Do not print unless the prompt asks.
    """
    # write your code here
    return []

Visible browser tests run here when available.

Testcases1 visible / 3 hidden categories

Core example

Inputtext = "PAYPAL", num_rows = 3

Expected["PA", "APL", "Y"]

Characters move down rows 0,1,2 and then back up row 1.

Hidden Test Categories

num_rows = 1text shorter than rowslonger string