Excluding empty values from RSD calculation

Question

Hello guys, 
 I met some kind of logic problem. Let me show you my situation: 
 This table is simply a results table filtered for one main compound (p-BFB) and I added columns with other compounds by datafile aggregator. The problem is when I am comparing some solutions, where compound m-BFB or BB is missing. I expected lines to be empty objects. Instead, OpenLab is converting empty values into 0 so if I want to calculate RSD from all occurrences it is calculating with 0. In my example, I am calculating the RSD of RT and when I have 2 standard injections and some sample injections in the set I have lines defined by the main peak and I am also going to have at least 2 impurities RT value but sometimes is sample clean and I do not have any peaks so I get 0. 
 Does somebody know some trick how to handle this situation? Thank you guys

martin.adams · Accepted Answer

Hello, 
 
 Typically, when I do that, I store the values in keyed variables on injection_ID. Below is a CC for RSD by compound, and sample type. You can change RT to other values get the RSD you want. You might also be able to report this data directly in the flexible matrix object. I did an example calculation attached as a PDF with the rdl file as a zip. The example does the calculation 3 ways, an IR table with conditional aggregators, CCF, and directly using a matrix. The custom calculation I used is below. 
 
 Marty 
 
 RelStdDev("Peak_RetentionTime",CurrentSequence.AllIdentifiedPeaks.Where(function (x) x.Compound_Name = CurrentPeakOrGroup.Compound_Name).Where(function (x) x.Injection.Sample.Sample_Type= CurrentInjection.Sample.Sample_Type)) 
 
 
 
 /cfs-file/__key/communityserver-discussions-components-files/26/Community-Example.zip

Excluding empty values from RSD calculation

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