How to format cell with datetime object of the form 'yyyy-mm-dd hh:mm:ss' in Excel using openpyxl

Question

So, given:

dttm = datetime.datetime.strptime("2014-06-23 13:56:30", "%Y-%m-%d %H:%M:%S")
ws['A1'] = dttm

The result in excel is that the correct date-time is written to the cell (you can see it where you'd input formulas). BUT, the cell display format is only MM/DD/YYYY.

I need the cell to display like "6/23/2014 13:56" instead of just "6/23/2014".

How can I explicitly format the cell to accomplish this?

Thanks!

Edit

@alecxe This solution works and is exactly what I asked for. I would like to be able to save styles like the solution by @Woodham. Unfortunately it raises a typeError (see comment). Any suggestions?

Answer 1

I'm adding this as a new answer since I don't have enough reputation to add a comment to the above. The simplest way to format a cell is using .number_format = "format" as in:

value = datetime.datetime.strptime("2014-06-23 13:56:30", "%Y-%m-%d %H:%M:%S")
cell = ws['A1']
cell.value = value
cell.number_format = 'YYYY MMM DD'

This is tested in openpyxl (2.2.2)

Answer 2

For openpyxl 2.4.5 you'll no longer have access to NumberFormat and Style and will have to use NamedStyle. Here's some sample usage:

from openpyxl.styles import NamedStyle

date_style = NamedStyle(name='datetime', number_format='DD/MM/YYYY HH:MM:MM')
ws['A1'].style = date_style

Alternatively with the new NamedStyle class, you can set the style by the string name once NamedStyle has been instantiated:

from openpyxl.styles import NamedStyle

NamedStyle(name='custom_datetime', number_format='DD/MM/YYYY HH:MM:MM')
ws['A1'].style = 'custom_datetime'

Documentation here: https://openpyxl.readthedocs.io/en/stable/styles.html

Answer 3

You can manually set the format_code:

value = datetime.datetime.strptime("2014-06-23 13:56:30", "%Y-%m-%d %H:%M:%S")
cell = ws['A1']
cell.value = value
cell.style.number_format.format_code = 'MM/DD/YY HH:MM'

Alternatively, you can call _set_number_format() method on the cell:

cell._set_number_format('MM/DD/YY HH:MM')

You can also define the style and reuse it, by setting ws._styles for a cell:

from openpyxl.styles import NumberFormat, Style

...

style = Style()
style.number_format = NumberFormat()
style.number_format.format_code = 'MM/DD/YY HH:MM'

ws['A1'] = value
ws._styles['A1'] = style

Tested - worked for me.

Answer 4

For openpyxl 2.3.4 the NumberFormat cannot be imported, but this code works to set the style:

from openpyxl.styles import Style

…
date_style = Style(number_format="DD/MM/YYYY HH:MM:MM")
ws['A1'].style = date_style

Answer 5

I believe you will need to set a openpyxl.styles.Style on the cell(s) that you want to format.

Looking at the documentation here, something like this should work:

dttm = datetime.datetime.strptime("2014-06-23 13:56:30", "%Y-%m-%d %H:%M:%S")
s = Style(number_format=NumberFormat('dd-mm-yyyy h:mm:ss'))

ws['A1'] = dttm
ws['A1'].styles = s

Update: Style class is no longer used, for the solution refer to this answer.