#0147

Days Between Dates

EasyPython15 min10 XP

Problem

Given two strings in YYYY-MM-DD format, return the absolute number of days between them.

Why This Matters

Date arithmetic is common in retention, subscriptions, experiment windows, and time-based feature engineering.

Function Signature

def days_between(a, b):

Examples

Example 1

Input"2026-01-01", "2026-01-10"

Output9

The difference from Jan 1 to Jan 10 is 9 full days.

Constraints

Return the exact requested value.
Handle empty or small inputs when the prompt allows them.
Keep the code readable and deterministic.

CodePython

def days_between(a, b):
    """
    Input example: "2026-01-01", "2026-01-10"
    Return: 9
    Return the value from the function so the tests can compare it. Do not print unless the prompt asks.
    """
    # write your code here
    return 0

def days_between(a, b):
    """
    Input example: "2026-01-01", "2026-01-10"
    Return: 9
    Return the value from the function so the tests can compare it. Do not print unless the prompt asks.
    """
    # write your code here
    return 0

Visible browser tests run here when available.

Testcases1 visible / 3 hidden categories

Core example

Input"2026-01-01", "2026-01-10"

Expected9

The difference from Jan 1 to Jan 10 is 9 full days.

Hidden Test Categories

empty or smallest inputduplicates or repeated valueslarger realistic input