Convert minutes:seconds:milliseconds into a seconds:milliseconds value

Numbers can convert to duration with the displayed style of ss.mmm.

Where you have 01:34:08 do you mean 1 minute 34 seconds and 8 milliseconds? Or do you mean 1 minute 34 seconds and 80 milliseconds?

Assuming you mean 1 minute 34 seconds and 8 milliseconds and you will be working with the values in Numbers (i.e. you're not just trying to convert and then use elsewhere) then you can do this.

1. Copy-paste the script below into Script Editor (in Application > Utilities)
2. The first time make sure Script Editor.app and Numbers.app are listed and checked at System Preferences > Security & Privacy > Privacy > Accessibility.
3. Select the cells in Numbers you want to convert to duration.
4. Click the triangle 'run' button in Script Editor.
5. Choose the Data Format pictured in the screenshot in the previous post (custom units sec and ms toggled on and style 00.000 selected)

As always, best to try this on a copy of your data first.

This should all take about a minute (no need to know AppleScript to use the script), and the results will be something like this:

You can work with these as duration values in Numbers or copy-paste elsewhere as needed. If by you meant 1 minute 34 seconds and 80 milliseconds post and will give you the necessary small adjustment to the script.

SG

The script (be sure to copy-paste everything in the box; some parts may scroll out of view to the right):

tell application "Numbers"
	tell front document's active sheet
		tell (first table whose selection range's class is range)
			repeat with c in (get selection range)'s cells
				set v to c's value
				set theDur to v's first word & "m " & v's second word & "s " & v's third word & "ms"
				set c's value to theDur
			end repeat
		end tell
	end tell
end tell

You mention seconds:milliseconds in your header but have xx.yy.zz in the text.

Numbers won't recognize . as the separator. Numbers can display the : as the separator.

However, when you enter duration values you would type 1m 17s 72ms or 77s 72ms.

Once you have entered a value and Numbers recognizes it as a duration (by default right-aligned) then you can change the way it is displayed if you want:

SG

If by 01:34:08 you meant 1 minute 34 seconds and 80 milliseconds the use this script instead. The other steps are the same, and should take a minute or so. It will give you something like this:

SG

tell application "Numbers"
	tell front document's active sheet
		tell (first table whose selection range's class is range)
			repeat with c in (get selection range)'s cells
				set v to c's value
				set min to v's first word
				set sec to v's second word
				set milsec to v's third word
				if milsec's length is 2 then
					set milsec to milsec & "0"
				end if
				set theDur to min & "m " & sec & "s " & milsec & "ms"
				set c's value to theDur
				set c's format to duration
			end repeat
		end tell
	end tell
end tell

 Is there anyway I can change to milliseconds to only 2 decimal
 points instead of the full three

If you're using the duration values further in Numbers then I think the answer is "no, that would confuse Numbers." It might also confuse human readers, as milliseconds are of course thousands of a second. It's a little like saying whenever I write the Number 8 what I really mean is 80.

However, if you are you taking the values and using them outside Numbers, you could do something like this:

I explicitly formatted the cells in column C as Text using the Data Format dropdown. Then I selected the values converted by the script, typed command-c to copy to the clipboard, clicked in C2 and chose Edit > Paste and Match Style from the menu to paste as text. Then I used the formula to chop off the last character. If the value is in C2, the formula would be: =LEFT(C2,LEN(C2)−1). Those truncated text values can then be copy-pasted elsewhere outside Numbers.

SG

I cannot adjust the milliseconds part to be less than three digits, either in the starting format of min:sec:ms or in the format you were asking for. The duration in the cell was entered as 1m 17s 72ms