CODEWITHSUNDEEP
pythonstringdatepandas
yoshiserry
yoshiserry

Reputation: 21345

how to convert string to date pandas python TypeError: strptime() takes no keyword arguments

I have a dataframe with some text dates in them. I would like to return the dates: year, month and day in separate columns. But in order to do that I need to first convert the text(from excel) to a date.

The code I have now is

def convertdate(dstring):
    dt = time.strptime(dstring, date_format='%Y-%m-%d')
    return dt

However it returns an: TypeError: strptime() takes no keyword arguments

Then instead of three separate functions for creating three separate columns, one for year, one for month, one for day.

Once the string is a date time object (dt), I believe the code is: return dt.year, return dt.month, return dt.day.

I would like one function which adds three columns to my dataframe, is this possible?

Upvotes: 3

Views: 17660

Answers (2)

InnocentBystander
InnocentBystander

Reputation: 711

Pandas now supports pandas.to_datetime for converting str to date. eg to create a new column of dates from a string col:

import pandas as pd
df['My Date'] = pd.to_datetime(df['Date Str'], format='%Y-%m-%d')

To split into numbers:

df['My Year'] = df['My Date'].apply(lambda x: x.year)
df['My Month'] = df['My Date'].apply(lambda x: x.month)
df['My Day'] = df['My Date'].apply(lambda x: x.day)

To split into string columns, use the .dt.strftime, eg for a month name like "Jan"

df['Month'] = df['My Date'].dt.strftime('%b')

More info: https://pandas.pydata.org/pandas-docs/stable/reference/api/pandas.to_datetime.html https://pandas.pydata.org/docs/reference/api/pandas.Series.dt.html

Upvotes: 0

falsetru
falsetru

Reputation: 369064

Pass the format string as a positional argument.

>>> import time
>>> def convertdate(dstring):
...     return time.strptime(dstring, '%Y-%m-%d')
...
>>> convertdate('2013-03-02')
time.struct_time(tm_year=2013, tm_mon=3, tm_mday=2, tm_hour=0, tm_min=0, tm_sec=0, tm_wday=5, tm_yday=61, tm_isdst=-1)

BTW, time.strptime returns time.struct_time. Its attributes are prefixed with tm_.

More preferably you can use datetime.datetime.strptime:

>>> import datetime
>>> import pandas as pd
>>>
>>> def convertdate(dstring):
...     return datetime.datetime.strptime(dstring, '%Y-%m-%d')
...
>>> dt = convertdate('2013-03-02')
>>> dt
datetime.datetime(2013, 3, 2, 0, 0)
>>> pd.DataFrame([{'year': dt.year, 'month': dt.month, 'day': dt.day}])
   day  month  year
0    2      3  2013

Upvotes: 3

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