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Delete row if two values in a matrix are equal

4 messages · Rui Barradas, JDINIS, arun

#
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"
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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#
Hello,

First, two notes:
1. 'var' is a really bad name for a variable, it already is an R function.
2. Your matrix seems more like a data.frame. The difference is important 
because data.frames by default coerce character strings to factors. I 
have tried to make the code work if this is the case or not.


vr <- 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
", header = TRUE)

yes <- as.character(vr[, "Ref_Allele"]) != as.character(vr[, "Var_Allele"])
vr[yes, ]



Hope this helps,

Rui Barradas

Em 26-10-2012 15:26, JDINIS escreveu:
#
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"
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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