RANKX not working

[kasperkc]

Hi 

I have a table of alarms filtered by data, now I would like make a Top N function, where the user can select the "See top N alarms". For this I have be trying to use the RANKX function, but i cannot get it for work proberly. Rank will not be done correltly in relation to the count. Seems that when the function finds and Alarm text that is used for more than one AlarmID, then it will not rank corretly 

I would like the function to rank my AlarmID based counts. 

Rank N = RANKX(all(Alarms[AlarmID]);[CountRows])

CountRows = COUNT(Alarms[AlarmID])

Here is my filtered data that I am trying to rank

AlarmID	Alarm text	Count of AlarmID	CountRows	Rank N	Top N within selected N
1000	Emergency stop activated - 130S5	2	2	1	1
1001	Power on is not activated - 131S2/131S5	2	2	1	1
1002	Safety door is not closed - 140K4	21	21	1	1
1003	Inlet safety gate is not closed - 146B5 - 145B11	2	2	1	1
1004	Outlet safety gate is not closed - 146B5 - 146B11	1	1	1	1
3086	No alarm text specified in HMI	3	3	5	1
3097	No alarm text specified in HMI	59	59	1	1
3098	No alarm text specified in HMI	55	55	2	1
5000	EM01 - Conveyor not initialized	9	9	1	1
5001	EM02 - Fixture 1 not initialized	9	9	1	1
5002	EM03 - Fixture 2 not initialized	9	9	1	1
5003	EM04 - Robot not initialized	8	8	1	1
5004	EM05 - Butyl not initialized	8	8	1	1
5020	No alarm text specified in HMI	11	11	4	1
5130	No alarm text specified in HMI	27	27	3	1

[HotChilli · Accepted solution]

This is all to do with context - and it's not straightforward to understand.  I think this is why RANKX causes so much confusion.  I'm pretty sure your Rank measure will work if you remove 'Alarm Text' from the visualisation.

When 'Alarm Text' is in the visualisation, it changes the context and you can see that in your example, it works only for rows where the text is the same.

If you ever need to work out what RANKX is doing, investigate RADACAD's concatenatex technique.

Short answer : If you want 'Alarm Text' in the visualisation, use

ALL(Alarms) instead of

ALL(Alarms[AlarmID])