Data Preprocessing: Pandas Conditionals and Preprocessing

Data Wrangling

Difficulty: 2 | Problem written by peter.washington

Educational Resource: https://web.stanford.edu/class/cs102/readings/pandasreferences.htm

Problem reported in interviews at


Given a pandas dataframe, run the following data preprocessing steps:

  1. If the value of col2 >= 1000, replace the value in col1 to 1000.
  2. Return a list of strings representing the values of col1.
Sample Input:
<class 'str'>
df: col1 col2 col3 0 1 2000 3 1 400 5 6 2 7 8 9

Expected Output:
<class 'pandas.core.frame.DataFrame'>
0 0 1000 1 400 2 7

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Jump to comment-90
rafi • 7¬†months, 2¬†weeks ago


Perform filtering

def data_preprocessing(df):
    df.loc[df['col2'] >= 1000, 'col1'] = 1000
    return [str(i) for i in df['col1']]



Input Test Case

Please enter only one test case at a time
numpy has been already imported as np (import numpy as np)