ConditionalFormatting of cell containing string in CAxlsx - ruby

Question

Using the CAxlsx gem (https://github.com/caxlsx/caxlsx), I'm trying to add conditional formatting to a range of cells, where the style should be applied if the cell contains the character -. Here's the snippet I'm using at the moment.
worksheet.add_conditional_formatting(range,
type: :containsText,
formula: "-",
dxfId: #styles[:invalid],
priority: 1)
Unfortunately, this doesn't seem to work. It does seem to apply the styling when the cell doesn't contain text, but a negative number, but that's not my use case. The documentation is severely lacking as well, and it doesn't offer a lot of explanation on what should be done in this case. (E.g., there's a cellIs type, with which the containsText operator can be used, but there's also a containsText type and no explanation as to what the difference between them is - and neither seem to work in my case.) Any pointers would be greatly appreciated, so far it's just been trial and error.

Answer 1

Assuming your range is something like "A1:A4" then formula you are looking for is NOT(ISERROR(SEARCH("-",A1))). Docs
Example:
require 'axlsx'
package = Axlsx::Package.new
workbook = package.workbook
s = workbook.styles.add_style({b:true, type: :dxf})
rows = ['a','b-c','d','e-f']
workbook.add_worksheet do |sheet|
rows.each do |row|
sheet.add_row [row]
end
sheet.add_conditional_formatting("A1:A4", { :type => :containsText,
:operator => :containsText,
:formula => 'NOT(ISERROR(SEARCH("-",A1)))',
:dxfId => s,
:priority => 1 })
end
package.serialize('conditional_test.xlsx')
I have found that the easiest way to determine the appropriate formula is to:
manually create a new excel work book
fill in an appropriate number of cells
conditionally format them in excel
save this workbook and close
change the extension to .zip (because xlsx is just zipped XML files)
open the zip file and navigate to /xl/worksheets/sheet1.xml
open this file and it will show you the formula used for the conditional formatting e.g.
<x14:conditionalFormattings>
<x14:conditionalFormatting xmlns:xm="http://schemas.microsoft.com/office/excel/2006/main">
<x14:cfRule type="containsText" priority="1" operator="containsText" id="{E75522C8-BC6E-4142-B282-D21DF586C852}">
<xm:f>NOT(ISERROR(SEARCH("-",A1)))</xm:f>
<xm:f>"-"</xm:f>
<x14:dxf>
<font>
<color rgb="FF9C0006"/>
</font>
<fill>
<patternFill>
<bgColor rgb="FFFFC7CE"/>
</patternFill>
</fill>
</x14:dxf>
</x14:cfRule>
<xm:sqref>A1:A4</xm:sqref>
</x14:conditionalFormatting>
</x14:conditionalFormattings>