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

Answer 1

from openpyxl import load_workbook
from openpyxl.styles import NamedStyle

xlsx_file = args.xlsx_file.name

# openning:
wb = load_workbook(filename = xlsx_file)


# create date style:
date_style = NamedStyle(name='date_style', number_format='DD.MM.YYYY HH:MM:MM')

# apply the style to the column H of the default sheet:
ws = wb.active
for row in ws[2:ws.max_row]:  # skip the header
    cell = row[7]             # column H
    cell.style = date_style

# saving:
wb.save(xlsx_file)

Edit: the above works for me, but somehow does not work on my coleagues machine. Converting the cell to string fixed that:

import datetime

from openpyxl import load_workbook
from openpyxl.styles import Alignment

xlsx_file = 'file.xlsx'

date_format = '%Y-%b-%d'

# openning:
wb = load_workbook(filename = xlsx_file)

# we also center align that column:
alignment = Alignment(horizontal='center')

# apply python date format to column H of the default sheet, and convert the column to Excel text:
ws = wb.active
for row in ws[2:ws.max_row]:        # skip the header
    cell = row[7]   # column H
    if isinstance(cell.value, datetime.datetime):
        cell.value = cell.value.strftime(date_format)
        cell.alignment = alignment

# saving:
wb.save(xlsx_file)

The same wrapped in a script:

#!/usr/bin/env python3

import argparse
import datetime

from openpyxl import load_workbook
from openpyxl.styles import Alignment


# ==============
## parsing args:

desc="""

Applies python date format to a given column of the xlsx file (default sheet) and converts the column to a Excel text format.

Dependencies:
pip3 install --user --upgrade openpyxl
"""

parser = argparse.ArgumentParser(description=desc, formatter_class=argparse.RawDescriptionHelpFormatter)
parser.add_argument('--version', action='version', version='%(prog)s 0.01')

parser.add_argument('-f', '--file',
                    help = "xlsx file",
                    dest = 'xlsx_file',
                    type = argparse.FileType('r'),
                    )

parser.add_argument('-c', '--column',
                    help = "column (starting from A) (default to %(default)s)",
                    dest = 'column',
                    type = str,
                    default = "A",
                    )

parser.add_argument('-d', '--date-format',
                    help = "date format to use, e.g. %%d.%%m.%%Y (default to %(default)s)",
                    dest = 'date_format',
                    type = str,
                    default = '%Y-%b-%d',
                    )

args = parser.parse_args()


# =========
## program:

xlsx_file = args.xlsx_file.name

column_number = sum(
    [ ord(char) - 97 + i*26  for i,char in enumerate(
        list( args.column.lower() )
        ) ]
)

# openning:
wb = load_workbook(filename = xlsx_file)

# we also center align that column:
alignment = Alignment(horizontal='center')

# apply python date format to a given column of the default sheet, and convert the column to Excel text:
ws = wb.active
for row in ws[2:ws.max_row]:        # skip the header
    cell = row[column_number]
    if isinstance(cell.value, datetime.datetime):
        cell.value = cell.value.strftime(args.date_format)
        cell.alignment = alignment

# saving:
wb.save(xlsx_file)