CODEWITHSUNDEEP
pythonpandasdataframe
anony123454323
anony123454323

Reputation: 71

How do I add a column to a dataframe using date as a filter

I'm trying to add a column from a pandas dataframe to another pandas dataframe using date columns to match them up. As you can see, one dataframe has one extra date I'd like to just skip. I figured an if statement would work for this but I'm getting: ValueError: Can only compare identically-labeled Series objects

          Date  Adj Close
0   2020-01-02   9.903333
1   2020-01-03   9.883333
2   2020-01-06   9.883333
3   2020-01-07   9.883333
4   2020-01-08   9.913333
..         ...        ...
163 2020-08-25  10.133333
164 2020-08-26  10.173333
165 2020-08-27  10.183333
166 2020-08-28  10.206667
167 2020-08-31  10.203334

[168 rows x 2 columns]
          Date  Capital Stock
0   2020-01-02        7251.39
1   2020-01-03       47200.86
2   2020-01-06      119020.28
3   2020-01-07    11751250.39
4   2020-01-08     4790267.25
..         ...            ...
162 2020-08-25        6348.29
163 2020-08-26      -11870.05
164 2020-08-27       73210.22
165 2020-08-28      120581.32
166 2020-08-31      134085.86

[167 rows x 2 columns]

here's what I've got!

if dshares_df['Date'] == price3['Date']:
    dshares_df['close'] = price3['Adj Close']

Upvotes: 0

Views: 22

Answers (1)

Moss
Moss

Reputation: 357

For this case you want to merge the two dataframes,

Try:

merged_df = dshares_df.merge(price3, on='Date')
# To filter out the extra row 
merged_df = merged_df.dropna()

see the docs: https://pandas.pydata.org/pandas-docs/stable/reference/api/pandas.DataFrame.merge.html

Upvotes: 1

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