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Challenge 104: Recipe Scaler

curriculum/challenges/english/blocks/daily-coding-challenges-python/68ffb91507a5b645769328c7.md

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--description--

Given an array of recipe ingredients and a number to scale the recipe, return an array with the quantities scaled accordingly.

  • Each item in the given array will be a string in the format: "quantity unit ingredient". For example "2 C Flour".
  • Scale the quantity by the given number. Do not include any trailing zeros and do not convert any units.
  • Return the scaled items in the same order they are given.

--hints--

scale_recipe(["2 C Flour", "1.5 T Sugar"], 2) should return ["4 C Flour", "3 T Sugar"].

js
({test: () => { runPython(`
from unittest import TestCase
TestCase().assertEqual(scale_recipe(["2 C Flour", "1.5 T Sugar"], 2), ["4 C Flour", "3 T Sugar"])`)
}})

scale_recipe(["4 T Flour", "1 C Milk", "2 T Oil"], 1.5) should return ["6 T Flour", "1.5 C Milk", "3 T Oil"].

js
({test: () => { runPython(`
from unittest import TestCase
TestCase().assertEqual(scale_recipe(["4 T Flour", "1 C Milk", "2 T Oil"], 1.5), ["6 T Flour", "1.5 C Milk", "3 T Oil"])`)
}})

scale_recipe(["3 C Milk", "2 C Oats"], 0.5) should return ["1.5 C Milk", "1 C Oats"].

js
({test: () => { runPython(`
from unittest import TestCase
TestCase().assertEqual(scale_recipe(["3 C Milk", "2 C Oats"], 0.5), ["1.5 C Milk", "1 C Oats"])`)
}})

scale_recipe(["2 C All-purpose Flour", "1 t Baking Soda", "1 t Salt", "1 C Butter", "0.5 C Sugar", "0.5 C Brown Sugar", "1 t Vanilla Extract", "2 C Chocolate Chips"], 2.5) should return ["5 C All-purpose Flour", "2.5 t Baking Soda", "2.5 t Salt", "2.5 C Butter", "1.25 C Sugar", "1.25 C Brown Sugar", "2.5 t Vanilla Extract", "5 C Chocolate Chips"].

js
({test: () => { runPython(`
from unittest import TestCase
TestCase().assertEqual(scale_recipe(["2 C All-purpose Flour", "1 t Baking Soda", "1 t Salt", "1 C Butter", "0.5 C Sugar", "0.5 C Brown Sugar", "1 t Vanilla Extract", "2 C Chocolate Chips"], 2.5), ["5 C All-purpose Flour", "2.5 t Baking Soda", "2.5 t Salt", "2.5 C Butter", "1.25 C Sugar", "1.25 C Brown Sugar", "2.5 t Vanilla Extract", "5 C Chocolate Chips"])`)
}})

--seed--

--seed-contents--

py
def scale_recipe(ingredients, scale):

    return ingredients

--solutions--

py
def scale_recipe(ingredients, scale):
    scaled = []

    for item in ingredients:
        parts = item.split(" ")
        quantity = float(parts[0]) * scale
        unit = parts[1]
        ingredient_name = " ".join(parts[2:])

        if quantity.is_integer():
            quantity_str = str(int(quantity))
        else:
            quantity_str = str(quantity)
        
        scaled.append(f"{quantity_str} {unit} {ingredient_name}")

    return scaled