Hi, I have a lab dataset where I want to take the first observation for each category for each visit and subject. This is how it looks: usubjid parameter visit 1001 chemistry screening 1001 chemistry screening 1001 chemistry screening 1001 chemistry screening 1001 Hematology screening 1001 Hematology screening 1001 Hematology screening 1001 urinalysis screening 1001 urinalysis screening 1001 urinalysis screening 1001 chemistry Day1 1001 chemistry Day1 1001 chemistry Day1 1001 hematology Day1 1001 hematology Day1 1001 urinalysis Day1 this is how data look like and have several subjects and another two visits. But the pattern is same. The desired data is: 1001 chemistry screening 1001 hematology screening 1001 urinalysis screening 1001 chemistry day1 1001 hematology day1 1001 urinalysis day1. Can someone please help with the code? Thanks Rashmi.
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