Convert SQL timestamp column to date format column of Python dataframe












0















I have data upload in MS Excel format.
enter image description here



This file has a column with dates in "dd.mm.yyyy 00:00:00" format.
Reading file with code:



df = pd.read_excel('data_from_db.xlsx')


I recieve a frame, where dates column has "object" type. Further I convert this column to date format by command:



df['Date_Column'] = pd.to_datetime(df['Date_Column'])


That gives me "datetime64[ns]" type.



But this command does not work correctly each time. I meet rows with muddled data:




  1. somewhere rows have format "yyyy.mm.dd",

  2. somwhere "yyyy.dd.mm".


How should I correctly convert excel column with "dd.mm.yyyy 00:00:00" format to column in pandas dataframe with date type and "dd.mm.yyyy" fromat?



P.S. Also, I noticed this oddity: some values in raw date column have str type, another - float. But I can't wrap my head around it, because raw table is an upload from database.










share|improve this question

























  • Hey there, welcome to StackOverflow! Please provide some more information, e.g. a sample of your data_from_db.xlsx. Have you checked the date format inside the spreadsheet, are they all 'dd.mm.yyyy'?

    – Finwood
    Nov 20 '18 at 9:57











  • @Finwood thank you for your attention - I uodated question with table image link.

    – Kate
    Nov 21 '18 at 13:22











  • @OleV.V. thank you for your advice - I've corrected tag

    – Kate
    Nov 21 '18 at 13:22
















0















I have data upload in MS Excel format.
enter image description here



This file has a column with dates in "dd.mm.yyyy 00:00:00" format.
Reading file with code:



df = pd.read_excel('data_from_db.xlsx')


I recieve a frame, where dates column has "object" type. Further I convert this column to date format by command:



df['Date_Column'] = pd.to_datetime(df['Date_Column'])


That gives me "datetime64[ns]" type.



But this command does not work correctly each time. I meet rows with muddled data:




  1. somewhere rows have format "yyyy.mm.dd",

  2. somwhere "yyyy.dd.mm".


How should I correctly convert excel column with "dd.mm.yyyy 00:00:00" format to column in pandas dataframe with date type and "dd.mm.yyyy" fromat?



P.S. Also, I noticed this oddity: some values in raw date column have str type, another - float. But I can't wrap my head around it, because raw table is an upload from database.










share|improve this question

























  • Hey there, welcome to StackOverflow! Please provide some more information, e.g. a sample of your data_from_db.xlsx. Have you checked the date format inside the spreadsheet, are they all 'dd.mm.yyyy'?

    – Finwood
    Nov 20 '18 at 9:57











  • @Finwood thank you for your attention - I uodated question with table image link.

    – Kate
    Nov 21 '18 at 13:22











  • @OleV.V. thank you for your advice - I've corrected tag

    – Kate
    Nov 21 '18 at 13:22














0












0








0








I have data upload in MS Excel format.
enter image description here



This file has a column with dates in "dd.mm.yyyy 00:00:00" format.
Reading file with code:



df = pd.read_excel('data_from_db.xlsx')


I recieve a frame, where dates column has "object" type. Further I convert this column to date format by command:



df['Date_Column'] = pd.to_datetime(df['Date_Column'])


That gives me "datetime64[ns]" type.



But this command does not work correctly each time. I meet rows with muddled data:




  1. somewhere rows have format "yyyy.mm.dd",

  2. somwhere "yyyy.dd.mm".


How should I correctly convert excel column with "dd.mm.yyyy 00:00:00" format to column in pandas dataframe with date type and "dd.mm.yyyy" fromat?



P.S. Also, I noticed this oddity: some values in raw date column have str type, another - float. But I can't wrap my head around it, because raw table is an upload from database.










share|improve this question
















I have data upload in MS Excel format.
enter image description here



This file has a column with dates in "dd.mm.yyyy 00:00:00" format.
Reading file with code:



df = pd.read_excel('data_from_db.xlsx')


I recieve a frame, where dates column has "object" type. Further I convert this column to date format by command:



df['Date_Column'] = pd.to_datetime(df['Date_Column'])


That gives me "datetime64[ns]" type.



But this command does not work correctly each time. I meet rows with muddled data:




  1. somewhere rows have format "yyyy.mm.dd",

  2. somwhere "yyyy.dd.mm".


How should I correctly convert excel column with "dd.mm.yyyy 00:00:00" format to column in pandas dataframe with date type and "dd.mm.yyyy" fromat?



P.S. Also, I noticed this oddity: some values in raw date column have str type, another - float. But I can't wrap my head around it, because raw table is an upload from database.







python excel pandas timestamp date-formatting






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edited Nov 21 '18 at 13:20







Kate

















asked Nov 20 '18 at 9:39









KateKate

12




12













  • Hey there, welcome to StackOverflow! Please provide some more information, e.g. a sample of your data_from_db.xlsx. Have you checked the date format inside the spreadsheet, are they all 'dd.mm.yyyy'?

    – Finwood
    Nov 20 '18 at 9:57











  • @Finwood thank you for your attention - I uodated question with table image link.

    – Kate
    Nov 21 '18 at 13:22











  • @OleV.V. thank you for your advice - I've corrected tag

    – Kate
    Nov 21 '18 at 13:22



















  • Hey there, welcome to StackOverflow! Please provide some more information, e.g. a sample of your data_from_db.xlsx. Have you checked the date format inside the spreadsheet, are they all 'dd.mm.yyyy'?

    – Finwood
    Nov 20 '18 at 9:57











  • @Finwood thank you for your attention - I uodated question with table image link.

    – Kate
    Nov 21 '18 at 13:22











  • @OleV.V. thank you for your advice - I've corrected tag

    – Kate
    Nov 21 '18 at 13:22

















Hey there, welcome to StackOverflow! Please provide some more information, e.g. a sample of your data_from_db.xlsx. Have you checked the date format inside the spreadsheet, are they all 'dd.mm.yyyy'?

– Finwood
Nov 20 '18 at 9:57





Hey there, welcome to StackOverflow! Please provide some more information, e.g. a sample of your data_from_db.xlsx. Have you checked the date format inside the spreadsheet, are they all 'dd.mm.yyyy'?

– Finwood
Nov 20 '18 at 9:57













@Finwood thank you for your attention - I uodated question with table image link.

– Kate
Nov 21 '18 at 13:22





@Finwood thank you for your attention - I uodated question with table image link.

– Kate
Nov 21 '18 at 13:22













@OleV.V. thank you for your advice - I've corrected tag

– Kate
Nov 21 '18 at 13:22





@OleV.V. thank you for your advice - I've corrected tag

– Kate
Nov 21 '18 at 13:22












1 Answer
1






active

oldest

votes


















0














Without specifying a format, pd.to_datetime has to guess from the data how a date string is to be interpreted. With default parameters this fails for the second and third row of your data:



In [5]: date_of_hire = pd.Series(['18.01.2018 0:00:00',
'01.02.2018 0:00:00',
'06.11.2018 0:00:00'])

In [6]: pd.to_datetime(date_of_hire)
Out[6]:
0 2018-01-18
1 2018-01-02
2 2018-06-11
dtype: datetime64[ns]


The quickest solution would be to pass dayfirst=True:



In [7]: pd.to_datetime(date_of_hire, dayfirst=True)
Out[7]:
0 2018-01-18
1 2018-02-01
2 2018-11-06
dtype: datetime64[ns]


If you know the complete format of your data, can specify it directly. This only works if the format is exactly like given, if a row should e.g. lack the time the conversion will fail.



In [8]: pd.to_datetime(date_of_hire, format='%d.%m.%Y %H:%M:%S')
Out[8]:
0 2018-01-18
1 2018-02-01
2 2018-11-06
dtype: datetime64[ns]


In case you should have little information about the date format, except for it being consistent, pandas has the ability to infer the format from the data beforehand:



In [9]: pd.to_datetime(date_of_hire, infer_datetime_format=True)
Out[9]:
0 2018-01-18
1 2018-02-01
2 2018-11-06
dtype: datetime64[ns]





share|improve this answer
























  • Thank you @Finwood for your comprehensive information. Your answer is really helpfull! Thanks you and StackOverflow :)

    – Kate
    Nov 27 '18 at 10:01













  • In this case, please mark the answer as accepted: stackoverflow.com/help/someone-answers

    – Finwood
    Nov 30 '18 at 5:56











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1 Answer
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active

oldest

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1 Answer
1






active

oldest

votes









active

oldest

votes






active

oldest

votes









0














Without specifying a format, pd.to_datetime has to guess from the data how a date string is to be interpreted. With default parameters this fails for the second and third row of your data:



In [5]: date_of_hire = pd.Series(['18.01.2018 0:00:00',
'01.02.2018 0:00:00',
'06.11.2018 0:00:00'])

In [6]: pd.to_datetime(date_of_hire)
Out[6]:
0 2018-01-18
1 2018-01-02
2 2018-06-11
dtype: datetime64[ns]


The quickest solution would be to pass dayfirst=True:



In [7]: pd.to_datetime(date_of_hire, dayfirst=True)
Out[7]:
0 2018-01-18
1 2018-02-01
2 2018-11-06
dtype: datetime64[ns]


If you know the complete format of your data, can specify it directly. This only works if the format is exactly like given, if a row should e.g. lack the time the conversion will fail.



In [8]: pd.to_datetime(date_of_hire, format='%d.%m.%Y %H:%M:%S')
Out[8]:
0 2018-01-18
1 2018-02-01
2 2018-11-06
dtype: datetime64[ns]


In case you should have little information about the date format, except for it being consistent, pandas has the ability to infer the format from the data beforehand:



In [9]: pd.to_datetime(date_of_hire, infer_datetime_format=True)
Out[9]:
0 2018-01-18
1 2018-02-01
2 2018-11-06
dtype: datetime64[ns]





share|improve this answer
























  • Thank you @Finwood for your comprehensive information. Your answer is really helpfull! Thanks you and StackOverflow :)

    – Kate
    Nov 27 '18 at 10:01













  • In this case, please mark the answer as accepted: stackoverflow.com/help/someone-answers

    – Finwood
    Nov 30 '18 at 5:56
















0














Without specifying a format, pd.to_datetime has to guess from the data how a date string is to be interpreted. With default parameters this fails for the second and third row of your data:



In [5]: date_of_hire = pd.Series(['18.01.2018 0:00:00',
'01.02.2018 0:00:00',
'06.11.2018 0:00:00'])

In [6]: pd.to_datetime(date_of_hire)
Out[6]:
0 2018-01-18
1 2018-01-02
2 2018-06-11
dtype: datetime64[ns]


The quickest solution would be to pass dayfirst=True:



In [7]: pd.to_datetime(date_of_hire, dayfirst=True)
Out[7]:
0 2018-01-18
1 2018-02-01
2 2018-11-06
dtype: datetime64[ns]


If you know the complete format of your data, can specify it directly. This only works if the format is exactly like given, if a row should e.g. lack the time the conversion will fail.



In [8]: pd.to_datetime(date_of_hire, format='%d.%m.%Y %H:%M:%S')
Out[8]:
0 2018-01-18
1 2018-02-01
2 2018-11-06
dtype: datetime64[ns]


In case you should have little information about the date format, except for it being consistent, pandas has the ability to infer the format from the data beforehand:



In [9]: pd.to_datetime(date_of_hire, infer_datetime_format=True)
Out[9]:
0 2018-01-18
1 2018-02-01
2 2018-11-06
dtype: datetime64[ns]





share|improve this answer
























  • Thank you @Finwood for your comprehensive information. Your answer is really helpfull! Thanks you and StackOverflow :)

    – Kate
    Nov 27 '18 at 10:01













  • In this case, please mark the answer as accepted: stackoverflow.com/help/someone-answers

    – Finwood
    Nov 30 '18 at 5:56














0












0








0







Without specifying a format, pd.to_datetime has to guess from the data how a date string is to be interpreted. With default parameters this fails for the second and third row of your data:



In [5]: date_of_hire = pd.Series(['18.01.2018 0:00:00',
'01.02.2018 0:00:00',
'06.11.2018 0:00:00'])

In [6]: pd.to_datetime(date_of_hire)
Out[6]:
0 2018-01-18
1 2018-01-02
2 2018-06-11
dtype: datetime64[ns]


The quickest solution would be to pass dayfirst=True:



In [7]: pd.to_datetime(date_of_hire, dayfirst=True)
Out[7]:
0 2018-01-18
1 2018-02-01
2 2018-11-06
dtype: datetime64[ns]


If you know the complete format of your data, can specify it directly. This only works if the format is exactly like given, if a row should e.g. lack the time the conversion will fail.



In [8]: pd.to_datetime(date_of_hire, format='%d.%m.%Y %H:%M:%S')
Out[8]:
0 2018-01-18
1 2018-02-01
2 2018-11-06
dtype: datetime64[ns]


In case you should have little information about the date format, except for it being consistent, pandas has the ability to infer the format from the data beforehand:



In [9]: pd.to_datetime(date_of_hire, infer_datetime_format=True)
Out[9]:
0 2018-01-18
1 2018-02-01
2 2018-11-06
dtype: datetime64[ns]





share|improve this answer













Without specifying a format, pd.to_datetime has to guess from the data how a date string is to be interpreted. With default parameters this fails for the second and third row of your data:



In [5]: date_of_hire = pd.Series(['18.01.2018 0:00:00',
'01.02.2018 0:00:00',
'06.11.2018 0:00:00'])

In [6]: pd.to_datetime(date_of_hire)
Out[6]:
0 2018-01-18
1 2018-01-02
2 2018-06-11
dtype: datetime64[ns]


The quickest solution would be to pass dayfirst=True:



In [7]: pd.to_datetime(date_of_hire, dayfirst=True)
Out[7]:
0 2018-01-18
1 2018-02-01
2 2018-11-06
dtype: datetime64[ns]


If you know the complete format of your data, can specify it directly. This only works if the format is exactly like given, if a row should e.g. lack the time the conversion will fail.



In [8]: pd.to_datetime(date_of_hire, format='%d.%m.%Y %H:%M:%S')
Out[8]:
0 2018-01-18
1 2018-02-01
2 2018-11-06
dtype: datetime64[ns]


In case you should have little information about the date format, except for it being consistent, pandas has the ability to infer the format from the data beforehand:



In [9]: pd.to_datetime(date_of_hire, infer_datetime_format=True)
Out[9]:
0 2018-01-18
1 2018-02-01
2 2018-11-06
dtype: datetime64[ns]






share|improve this answer












share|improve this answer



share|improve this answer










answered Nov 22 '18 at 16:05









FinwoodFinwood

2,53011031




2,53011031













  • Thank you @Finwood for your comprehensive information. Your answer is really helpfull! Thanks you and StackOverflow :)

    – Kate
    Nov 27 '18 at 10:01













  • In this case, please mark the answer as accepted: stackoverflow.com/help/someone-answers

    – Finwood
    Nov 30 '18 at 5:56



















  • Thank you @Finwood for your comprehensive information. Your answer is really helpfull! Thanks you and StackOverflow :)

    – Kate
    Nov 27 '18 at 10:01













  • In this case, please mark the answer as accepted: stackoverflow.com/help/someone-answers

    – Finwood
    Nov 30 '18 at 5:56

















Thank you @Finwood for your comprehensive information. Your answer is really helpfull! Thanks you and StackOverflow :)

– Kate
Nov 27 '18 at 10:01







Thank you @Finwood for your comprehensive information. Your answer is really helpfull! Thanks you and StackOverflow :)

– Kate
Nov 27 '18 at 10:01















In this case, please mark the answer as accepted: stackoverflow.com/help/someone-answers

– Finwood
Nov 30 '18 at 5:56





In this case, please mark the answer as accepted: stackoverflow.com/help/someone-answers

– Finwood
Nov 30 '18 at 5:56




















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