CODEWITHSUNDEEP
pythonpandas
user1610719
user1610719

Reputation: 1303

Adding days to column in pandas using separate column integers

I've tried datetime.timedelta on the series, as well as pd.DateOffset. Neither works. I do know I could iterate over this dataframe and add them manually, but I was looking for a vectorized approach.

Example:

d = {pd.Timestamp('2015-01-02'):{'days_delinquent':11}, pd.Timestamp('2015-01-15'):{'days_delinquent':23}}
>>> dataf = pd.DataFrame.from_dict(d,orient='index')
>>> dataf
            days_delinquent
2015-01-02               11
2015-01-15               23

Just trying to add 11 and 23 days to the rows below. The column I'm adding to in real life is not the index, but I can obviously just make it the index when doing this.

I guess this wasn't self explanatory, but the output would the be a new column with Date(Index in this case) + datetime.timedelta(days=dataf['days_delinquent'])

Upvotes: 1

Views: 75

Answers (3)

Jon Clements
Jon Clements

Reputation: 142166

You can convert your days_delinquent column to timedelta64[D] (offset in days) and add it to the index, eg:

import pandas as pd

d = {pd.Timestamp('2015-01-02'):{'days_delinquent':11}, pd.Timestamp('2015-01-15'):{'days_delinquent':23}}
df = pd.DataFrame.from_dict(d,orient='index')
df['returned_on'] = df.index + df.days_delinquent.astype('timedelta64[D]')

Much nicer (thanks DSM) is to use pd.to_timedelta so the units are more easily changed if needs be:

df['returned_on'] = df.index + pd.to_timedelta(df.days_delinquent, 'D')

Gives you:

            days_delinquent returned_on
2015-01-02               11  2015-01-13
2015-01-15               23  2015-02-07

Upvotes: 3

Alexander
Alexander

Reputation: 109546

dataf['result'] = [d + datetime.timedelta(delta) 
                   for d, delta in zip(dataf.index, dataf.days_delinquent)]

dataf
Out[56]: 
            days_delinquent     result
2015-01-02               11 2015-01-13
2015-01-15               23 2015-02-07

Upvotes: 1

Liam Foley
Liam Foley

Reputation: 7822

import pandas as pd

d = {pd.Timestamp('2015-01-02'):{'days_delinquent':11}, 
    pd.Timestamp('2015-01-15'):{'days_delinquent':23}}
df = pd.DataFrame.from_dict(d,orient='index')

def add_days(x):
    return x['index'] + pd.Timedelta(days=x['days_delinquent'])

df.reset_index().apply(add_days,axis=1)

Output:

0   2015-01-13
1   2015-02-07
dtype: datetime64[ns]

Upvotes: 1

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