[R] Delete row if two values in a matrix are equal

[arun]

Hi,
You can try either one of these:
dat1<-read.table(text="
Ref_Pos    Ref_Allele    Var_Allele    Var_Freq
      1            A                  A                100
      2                    T                  G                  50
      3                    G                  G                100
      4                    G                  T                  45
      5                    T                  C                  80
",sep="",header=TRUE,stringsAsFactors=FALSE)


dat2<-dat1[unlist(lapply(split(dat1[,2:3],1:nrow(dat1[,2:3])),function(x) unlist(gregexpr(x[1],x[2]))!=1),use.names=FALSE),]
dat2
#  Ref_Pos Ref_Allele Var_Allele Var_Freq
#2       2          T          G       50
#4       4          G          T       45
#5       5          T          C       80

#or

dat3<-dat1[apply(dat1,1,function(x) x[2]!=x[3]),]
dat3
#  Ref_Pos Ref_Allele Var_Allele Var_Freq
#2       2          T          G       50
#4       4          G          T       45
#5       5          T          C       80

#or

dat4<-dat1[dat1[,2]!=dat1[,3],]
dat4
#  Ref_Pos Ref_Allele Var_Allele Var_Freq
#2       2          T          G       50
#4       4          G          T       45
#5       5          T          C       80
identical(dat2,dat3)
#[1] TRUE
identical(dat2,dat4)
#[1] TRUE

A.K.



----- Original Message -----
From: JDINIS <jorgemdinis at gmail.com>
To: r-help at r-project.org
Cc: 
Sent: Friday, October 26, 2012 10:26 AM
Subject: [R] Delete row if two values in a matrix are equal

Hi all and thank you for your time. 

I would like to delete rows from this matrix I call "var" if the character
in Ref_Allele is equal to the character in Var_Allele. I have attached a
before and after, to help my poor explanation. If someone could provide me
with some code, or some guidance I would really appreciate it.

Thank you again.

"Before"
> var
Ref_Pos    Ref_Allele    Var_Allele    Var_Freq
     1             A                  A                 100
     2                    T                  G                  50
     3                    G                  G                 100
     4                    G                  T                  45
     5                     T                  C                  80



"After"
Ref_Pos    Ref_Allele    Var_Allele    Var_Freq
     2                    T                  G                  50
     4                    G                  T                  45
     5                     T                  C                  80




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