r - Remove row if certain variable is the same as the row above -

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• select first rows each unique value of column in r 7 answers

i build on question similar remove rows data frame row match string

for example:

a,b,org.id 4,3,foo 2,3,bar 2,4,bar 7,5,zap 7,4,zap 7,3,zap 

how return dataframe excludes rows org.id same row above?

a,b,org.id 4,3,foo 2,3,bar 7,5,zap 

guess: perhaps melt() or cast() functions trick. (i know how in excel, have create new dataframe , if[a2=a1,0,a2].)

the question similar subtract previous row of data id same row above in sql.

you can try duplicated

 df1[!duplicated(df1$org.id),]  #   b org.id  #1 4 3    foo  #2 2 3    bar  #4 7 5    zap 

or using unique by option

 library(data.table)  unique(setdt(df1), by='org.id')