Hello, I am cleaning our database and trying to re-contact the participants a second time to acquire information in order to reduce missing values. For example, I have 1000 participants and 200 variables. I want to output participants whose data are missing for 100 key variables among the 200 variables. Participant A may only have 2 variables with missing values and participant B may have 30 variables with missing values. I don't know how to output participants with missing values. The hypothetical dataset as shown below, I want to output participant1 showing var2, var4 with missing values; and participant2 showing var1, var3, var4 and var5 with missing values; Thanks a lot! Jing Yuan no var1 var2 var3 var4 var5 var6 1 128 . 45 . 44 67 2 . 34 . . 66 . 3 235 . . 56 . 78 4 321 . 56 . . 66 5 214 . . . . 68
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