Is there a way to use eval to calculate the standard deviation of data in multiple fields (same number of fields each time) for a single event? Right now I am using an eval statement that writes out the entire Standard Deviation formula.
| eval StDev = round(pow((pow(field1-fieldsAvg, 2)+pow(field2-fieldsAvg, 2)+pow(field3-fieldsAvg, 2)+pow(field4-fieldsAvg, 2)+pow(field5-fieldsAvg, 2))/5, 1/2), 4)
Each line of my table represents a different event that needs this calculation.
Since Standard deviation is calculated using average so I am assuming your field called
fieldsAvg is the average of all the five fields. Which also makes me feel we can tweak your situation as follows:
- Make a new field called
myField which has values from all the five fields. So if you have 3 events with 5 field values each, this new field will have 15 values to take care of all 5 fields for all 3 events.
- Calculate the stdev on this new field
your base query to return field1,field2,field3,field4,field5 | eval myField=mvzip(field1, mvzip(field2, mvzip(field3, mvzip(field4, field5)))) | mvexpand myField | rex max_match=0 field=myField "(?<numbers>\d+)" | stats stdev(numbers) as stdDeviation
Yes, I do have the
fieldsAvg calculated separately.
In your explanation, you say that 5 values from 3 events will all end up in
myField together. What if I still want to keep the Standard Deviations separate by events?
You could improve your current solution by making a macro out of it, which would be easier to use and maintain across different searches without worrying about a typo causing one of them to behave differently.
My understanding is there is no
eval function that will calculate the standard deviation for fields in the same row.
Most of the
eval functions are designed to be performed across all of the rows against specific fields (e.g., the standard deviation for your field "field1").