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Dunder Data Challenge #5 — Keeping Values Within the Interquartile Range

dunder data challenges Nov 14, 2019

In this challenge, you are given a table of closing stock prices for 10 different stocks with data going back as far as 1999. For each stock, calculate the interquartile range (IQR). Return a DataFrame that satisfies the following conditions:

  • Keep values as they are if they are within the IQR
  • For values lower than the first quartile, make them equal equal to the exact value of the first quartile
  • For values higher than the third quartile, make them equal equal to the exact value of the third quartile

Start this challenge in a Jupyter Notebook right now thanks to Binder (

import pandas as pd
stocks = pd.read_csv('../data/stocks10.csv', index_col='date', parse_dates=['date'])


There is a straightforward solution that completes this challenge in a single line of readable code. Can you find it?

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