从R中的矩阵中删除重复的行

Question

I have a matrix that is similar to

 2013  1  0    
 2013  1  30
 2013  1  100
 2013  2  0
 2013  2  30
 2013  2  100
 2013  3  0
 2013  3  30
 2013  3  100
 2013  1  0
 2013  1  30
 2013  4  0

Where there are extra columns after the third that have extra data. I need a way to remove the duplicate rows. In this example I would need to remove the rows that had a 1 in the second column. Is there a way to remove these rows while maintaining the rest of my data.

I have tried unique() and duplicate() and could not produce what I need. if I matrix was m.dat I tried using

m.dat <- m.dat[-duplicated(m.dat[,2:3])]

but that doesn't work. Am I using duplicate wrong or is there another way to do this?

Answer 1

m.dat<-m.dat[m.dat[ ,2]!=1, ]

or

m.dat<-m.dat[!(m.dat[ ,2]==1 & duplicated(m.dat[,1:3]) , ]

depending on what you're looking for. I am somewhat confused if you want to remove just records with value '1' in the second column or those with '1' and which are also duplicate rows

if you wanted to know what numbers are repeated in that column you could use something like

reps<-unique(m.dat[,2][duplicated(m.dat[,2])])

and then remove all of these with a %in% statement

something like...

m.dat<-m.dat[ ! m.dat[,2] %in% unique(m.dat[,2][duplicated(m.dat[,2])]) ,]

Answer 2

I was able to figure it out. What I used was

 m <- duplicated(m.dat[,3:4])
 m <- as.numeric(m)
 ind = which(m ==1)
 m.dat = m.dat[-ind,]