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Python Data Cleaning and Merge
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Python Data Cleaning and Merge

MediumSQL · PostgreSQL

Problem

Write a Python script using Pandas and NumPy to load two separate dataframes, clean missing values, and merge them on a specific key.

For this SQL version, clean the nullable attributes and combine records using record_key. Exclude rows where the source record key is NULL.

Output

  1. One row per non-NULL record in dataframe_a
  2. Columns: record_key, subject_name, measurement, category, and review_status
  3. Replace missing attributes with their specified defaults and show unmatched records with NULL joined attributes
  4. Sort by record_key ascending

Schema

dataframe_a
ColumnTypeDescription
record_keyINTEGERIdentifier used to match records across both datasets
subject_nameVARCHAR(100)Subject or record name
measurementNUMERIC(12,2)Numeric measurement associated with the record
dataframe_b
ColumnTypeDescription
record_keyINTEGERIdentifier used to match records across both datasets
categoryVARCHAR(100)Classification associated with the record
review_statusVARCHAR(50)Current review status
Tablesdataframe_adataframe_b
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