Working with styles

Introduction

Styles are used to change the look of your data while displayed on screen. They are also used to determine the formatting for numbers.

Styles can be applied to the following aspects:

  • font to set font size, color, underlining, etc.

  • fill to set a pattern or color gradient

  • border to set borders on a cell

  • cell alignment

  • protection

The following are the default values

>>> from openpyxl.styles import PatternFill, Border, Side, Alignment, Protection, Font
>>> font = Font(name='Calibri',
...                 size=11,
...                 bold=False,
...                 italic=False,
...                 vertAlign=None,
...                 underline='none',
...                 strike=False,
...                 color='FF000000')
>>> fill = PatternFill(fill_type=None,
...                 start_color='FFFFFFFF',
...                 end_color='FF000000')
>>> border = Border(left=Side(border_style=None,
...                           color='FF000000'),
...                 right=Side(border_style=None,
...                            color='FF000000'),
...                 top=Side(border_style=None,
...                          color='FF000000'),
...                 bottom=Side(border_style=None,
...                             color='FF000000'),
...                 diagonal=Side(border_style=None,
...                               color='FF000000'),
...                 diagonal_direction=0,
...                 outline=Side(border_style=None,
...                              color='FF000000'),
...                 vertical=Side(border_style=None,
...                               color='FF000000'),
...                 horizontal=Side(border_style=None,
...                                color='FF000000')
...                )
>>> alignment=Alignment(horizontal='general',
...                     vertical='bottom',
...                     text_rotation=0,
...                     wrap_text=False,
...                     shrink_to_fit=False,
...                     indent=0)
>>> number_format = 'General'
>>> protection = Protection(locked=True,
...                         hidden=False)
>>>

Cell Styles and Named Styles

There are two types of styles: cell styles and named styles, also known as style templates.

Cell Styles

Cell styles are shared between objects and once they have been assigned they cannot be changed. This stops unwanted side-effects such as changing the style for lots of cells when only one changes.

>>> from openpyxl.styles import colors
>>> from openpyxl.styles import Font, Color
>>> from openpyxl import Workbook
>>> wb = Workbook()
>>> ws = wb.active
>>>
>>> a1 = ws['A1']
>>> d4 = ws['D4']
>>> ft = Font(color="FF0000")
>>> a1.font = ft
>>> d4.font = ft
>>>
>>> a1.font.italic = True # is not allowed 
>>>
>>> # If you want to change the color of a Font, you need to reassign it::
>>>
>>> a1.font = Font(color="FF0000", italic=True) # the change only affects A1

Copying styles

Styles can also be copied

>>> from openpyxl.styles import Font
>>> from copy import copy
>>>
>>> ft1 = Font(name='Arial', size=14)
>>> ft2 = copy(ft1)
>>> ft2.name = "Tahoma"
>>> ft1.name
'Arial'
>>> ft2.name
'Tahoma'
>>> ft2.size # copied from the
14.0

Colours

Colours for fonts, backgrounds, borders, etc. can be set in three ways: indexed, aRGB or theme. Indexed colours are the legacy implementation and the colours themselves depend upon the index provided with the workbook or with the application default. Theme colours are useful for complementary shades of colours but also depend upon the theme being present in the workbook. It is, therefore, advisable to use aRGB colours.

aRGB colours

RGB colours are set using hexadecimal values for red, green and blue.

>>> from openpyxl.styles import Font
>>> font = Font(color="FF0000")

The alpha value refers in theory to the transparency of the colour but this is not relevant for cell styles. The default of 00 will prepended to any simple RGB value:

>>> from openpyxl.styles import Font
>>> font = Font(color="00FF00")
>>> font.color.rgb
'0000FF00'

There is also support for legacy indexed colours as well as themes and tints.

>>> from openpyxl.styles.colors import Color
>>> c = Color(indexed=32)
>>> c = Color(theme=6, tint=0.5)

Indexed Colours

Standard Colours
Index
0-4 00000000 00FFFFFF 00FF0000 0000FF00 000000FF
5-9 00FFFF00 00FF00FF 0000FFFF 00000000 00FFFFFF
10-14 00FF0000 0000FF00 000000FF 00FFFF00 00FF00FF
15-19 0000FFFF 00800000 00008000 00000080 00808000
20-24 00800080 00008080 00C0C0C0 00808080 009999FF
25-29 00993366 00FFFFCC 00CCFFFF 00660066 00FF8080
30-34 000066CC 00CCCCFF 00000080 00FF00FF 00FFFF00
35-39 0000FFFF 00800080 00800000 00008080 000000FF
40-44 0000CCFF 00CCFFFF 00CCFFCC 00FFFF99 0099CCFF
45-49 00FF99CC 00CC99FF 00FFCC99 003366FF 0033CCCC
50-54 0099CC00 00FFCC00 00FF9900 00FF6600 00666699
55-60 00969696 00003366 00339966 00003300 00333300
60-63 00993300 00993366 00333399 00333333

The indices 64 and 65 cannot be set and are reserved for the system foreground and background colours respectively.

Applying Styles

Styles are applied directly to cells

>>> from openpyxl.workbook import Workbook
>>> from openpyxl.styles import Font, Fill
>>> wb = Workbook()
>>> ws = wb.active
>>> c = ws['A1']
>>> c.font = Font(size=12)

Columns and Rows

Styles can also applied to columns and rows but note that this applies only to cells created (in Excel) after the file is closed. If you want to apply styles to entire rows and columns then you must apply the style to each cell individually. This is a restriction of the file format:

>>> col = ws.column_dimensions['A']
>>> col.font = Font(bold=True)
>>> row = ws.row_dimensions[1]
>>> row.font = Font(underline="single")

Note

Column dimensions can be grouped, although this is primarily for outline purposes, it can also be used for other attributes, which can be confusing because only the first column of the group will be listed. Use ws.column_groups to check.

Styling Merged Cells

The merged cell behaves similarly to other cell objects. Its value and format is defined in its top-left cell. In order to change the border of the whole merged cell, change the border of its top-left cell. The formatting is generated for the purpose of writing.

>>> from openpyxl.styles import Border, Side, PatternFill, Font, GradientFill, Alignment
>>> from openpyxl import Workbook
>>>
>>> wb = Workbook()
>>> ws = wb.active
>>> ws.merge_cells('B2:F4')
>>>
>>> top_left_cell = ws['B2']
>>> top_left_cell.value = "My Cell"
>>>
>>> thin = Side(border_style="thin", color="000000")
>>> double = Side(border_style="double", color="ff0000")
>>>
>>> top_left_cell.border = Border(top=double, left=thin, right=thin, bottom=double)
>>> top_left_cell.fill = PatternFill("solid", fgColor="DDDDDD")
>>> top_left_cell.fill = fill = GradientFill(stop=("000000", "FFFFFF"))
>>> top_left_cell.font  = Font(b=True, color="FF0000")
>>> top_left_cell.alignment = Alignment(horizontal="center", vertical="center")
>>>
>>> wb.save("styled.xlsx")

Using number formats

You can specify the number format for cells, or for some instances (ie datetime) it will automatically format.

>>> import datetime
>>> from openpyxl import Workbook
>>> wb = Workbook()
>>> ws = wb.active
>>> # set date using a Python datetime
>>> ws['A1'] = datetime.datetime(2010, 7, 21)
>>>
>>> ws['A1'].number_format
'yyyy-mm-dd h:mm:ss'
>>>
>>> ws["A2"] = 0.123456
>>> ws["A2"].number_format = "0.00" # Display to 2dp

Edit Page Setup

>>> from openpyxl.workbook import Workbook
>>>
>>> wb = Workbook()
>>> ws = wb.active
>>>
>>> ws.page_setup.orientation = ws.ORIENTATION_LANDSCAPE
>>> ws.page_setup.paperSize = ws.PAPERSIZE_TABLOID
>>> ws.page_setup.fitToHeight = 0
>>> ws.page_setup.fitToWidth = 1

Named Styles

In contrast to Cell Styles, Named Styles are mutable. They make sense when you want to apply formatting to lots of different cells at once. NB. once you have assigned a named style to a cell, additional changes to the style will not affect the cell.

Once a named style has been registered with a workbook, it can be referred to simply by name.

Creating a Named Style

>>> from openpyxl.styles import NamedStyle, Font, Border, Side
>>> highlight = NamedStyle(name="highlight")
>>> highlight.font = Font(bold=True, size=20)
>>> bd = Side(style='thick', color="000000")
>>> highlight.border = Border(left=bd, top=bd, right=bd, bottom=bd)

Once a named style has been created, it can be registered with the workbook:

>>> wb.add_named_style(highlight)

But named styles will also be registered automatically the first time they are assigned to a cell:

>>> ws['A1'].style = highlight

Once registered, assign the style using just the name:

>>> ws['D5'].style = 'highlight'

Using builtin styles

The specification includes some builtin styles which can also be used. Unfortunately, the names for these styles are stored in their localised forms. openpyxl will only recognise the English names and only exactly as written here. These are as follows:

  • ‘Normal’ # same as no style

Number formats

  • ‘Comma’

  • ‘Comma [0]’

  • ‘Currency’

  • ‘Currency [0]’

  • ‘Percent’

Informative

  • ‘Calculation’

  • ‘Total’

  • ‘Note’

  • ‘Warning Text’

  • ‘Explanatory Text’

Text styles

  • ‘Title’

  • ‘Headline 1’

  • ‘Headline 2’

  • ‘Headline 3’

  • ‘Headline 4’

  • ‘Hyperlink’

  • ‘Followed Hyperlink’

  • ‘Linked Cell’

Comparisons

  • ‘Input’

  • ‘Output’

  • ‘Check Cell’

  • ‘Good’

  • ‘Bad’

  • ‘Neutral’

Highlights

  • ‘Accent1’

  • ‘20 % - Accent1’

  • ‘40 % - Accent1’

  • ‘60 % - Accent1’

  • ‘Accent2’

  • ‘20 % - Accent2’

  • ‘40 % - Accent2’

  • ‘60 % - Accent2’

  • ‘Accent3’

  • ‘20 % - Accent3’

  • ‘40 % - Accent3’

  • ‘60 % - Accent3’

  • ‘Accent4’

  • ‘20 % - Accent4’

  • ‘40 % - Accent4’

  • ‘60 % - Accent4’

  • ‘Accent5’

  • ‘20 % - Accent5’

  • ‘40 % - Accent5’

  • ‘60 % - Accent5’

  • ‘Accent6’

  • ‘20 % - Accent6’

  • ‘40 % - Accent6’

  • ‘60 % - Accent6’

  • ‘Pandas’

For more information about the builtin styles please refer to the openpyxl.styles.builtins