search for: participid

Hi, I need to subset different levels of vector in a dataset to create a new dataframe that contains only these. These observations are not numerical, so I can't use the subset() function (at least this is the response I get from R). Suppose the dataframe looks like this:   ParticipID    ERP   Electrode 1         s1  0.0370       FP1 2         s2 35.0654       FP2 3         s3 -3.3852        F4 4         s4  2.6119        P3 5         s5  0.1224        P4 6         s6 -5.3153        O1 I want to create a subset of the dataframe with only the FP1, FP2, F4 levels of Electrode, h...