Python Pandas – Lookup a variable column depending on another column’s value

by

Let us do numpy way since lookup will not longer work in the future version

df['new'] = df.values[df.index,df.columns.get_indexer(df.source)]
df
Out[339]: 
        A       B source     new
0    John    Fred      A    John
1  Andrew   Simon      B   Simon
2     Bob  Andrew      A     Bob
3    Fred  Andrew      B  Andrew

More Related Contents:

  1. How to change column names from numbers to names [closed]
  2. How to provide a reproducible copy of your DataFrame with to_clipboard()
  3. How to replace NaNs by preceding or next values in pandas DataFrame?
  4. Find column whose name contains a specific string
  5. Calculate average of every x rows in a table and create new table
  6. Conditionally fill column values based on another columns value in pandas
  7. How to deal with multi-level column names downloaded with yfinance
  8. Rolling Mean on pandas on a specific column
  9. Pandas deleting row with df.drop doesn’t work
  10. Count number of words per row
  11. What is the fastest and most efficient way to append rows to a DataFrame?
  12. Updating a value in a pandas dataframe in an iterrows loop
  13. append dictionary to data frame
  14. Python pandas: how to remove nan and -inf values
  15. Check if rows in one dataframe exist in another dataframe
  16. How to convert string representation of dictionary in Pandas DataFrame to a new columns?
  17. Confusion about pandas copy of slice of dataframe warning
  18. How do I transpose dataframe in pandas without index?
  19. How to select all columns whose names start with X in a pandas DataFrame
  20. Remove reverse duplicates from dataframe
  21. How to split text in a column into multiple rows
  22. Pandas merge two dataframes with different columns
  23. Pandas filter dataframe rows with a specific year
  24. Apply function to each cell in DataFrame
  25. Pandas number rows within group in increasing order
  26. Store numpy.array in cells of a Pandas.DataFrame
  27. Set value on an entire column of a pandas dataframe
  28. AttributeError: module ‘numpy’ has no attribute ‘__version__’
  29. UnicodeDecodeError when reading CSV file in Pandas
  30. how to understand closed and label arguments in pandas resample method?

Leave a Comment