CODEWITHSUNDEEP
pythonpandas
AME
AME

Reputation: 5300

Transforming a Date Column with Pandas

I would like to transform a column in my data set that has number of days from the start date of a period into a date.

Here's an example of what I am trying to achieve in pandas:

enter image description here

#This doesn't not work 
sdate = datetime(2015, 10, 1)
ndf['Date'] = ndf['Date'].apply(lambda x: sdate + x)

Upvotes: 1

Views: 70

Answers (1)

Anand S Kumar
Anand S Kumar

Reputation: 90859

You would need to convert your 'Date' column to timedelta and then add the sdate to it.

An Example of vectorized way of doing it -

sdate = datetime(2015, 10, 1)
ndf['Date'] = pd.to_timedelta(ndf['Date'],unit='d') + sdate

This would make the column to be of type datetime (not string).

Demo -

In [18]: from datetime import datetime

In [19]: sdate = datetime(2015, 10, 1)

In [20]: df
Out[20]:
   Date
0     1
1     1
2     3
3     5

In [21]: df['Date'] = pd.to_timedelta(df['Date'],unit='d') + sdate

In [22]: df
Out[22]:
        Date
0 2015-10-02
1 2015-10-02
2 2015-10-04
3 2015-10-06

Upvotes: 2

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