R help - May 2013 - how to merge 2 data frame if you want to exclude mutual obs

In the example below, I am merging 2 data frames & I want everything in the
first one(all)
all2 <- merge(all,spets, by.x=c("tdate","symbol"),
by.y=c("tdate","symbol"),all.x=TRUE)

What if I want to exclude everything in y? I tried below but doesn't seem to
work.
all2 <- merge(all,spets, by.x=c("tdate","symbol"),
by.y=c("tdate","symbol"),all.y=FALSE)

In SAS I  would do:

All2;
  merge all(in=a)
             spetz(in=b)
            ;
 by tdate symbol;
 if a and not b;
run;

How can I do this in R?
Thanks ahead for your help.



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To clarify:

So if in data frame A you have

Tdate            symbol        TA
12/12/12      AX               123
12/11/12      ZZ                A4R
12/12/12      WQ              B8R

Data frame B
Tdate            symbol        TA
12/12/12      AX               123
12/11/12      ZZ                A4R

I want to end up w/
Tdate            symbol        TA
12/12/12      WQ              B8R

All obs not in B




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If you create a dummy variable for spets prior to merging, you can keep
only those rows where this value is missing after merging.  For example:

# fake data
all <- data.frame(tdate=c(1, 3, 5, 7), symbol=c(2, 4, 6, 8))
spets <- data.frame(tdate=c(1, 3, 5, 2), symbol=c(2, 8, 6, 6))

# create a dummy variable for spets
spets$dummy <- 1

# merge
all2 <- merge(all, spets, by=c("tdate", "symbol"),
all.x=TRUE)
all3 <- all2[is.na(all2$dummy), ]
all3

Jean

	[[alternative HTML version deleted]]

Thanks Adam your solution worked perfectly.  Thank you all for your
responses.



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Hi,
datA<-read.table(text="
Tdate??????????? symbol??????? TA
12/12/12????? AX????????????? 123
12/11/12????? ZZ??????????????? A4R
12/12/12????? WQ????????????? B8R
",sep="",header=TRUE,stringsAsFactors=FALSE)
datB<- read.table(text="
Tdate??????????? symbol??????? TA
12/12/12????? AX????????????? 123
12/11/12????? ZZ??????????????? A4R
",sep="",header=TRUE,stringsAsFactors=FALSE)
library(sqldf)
sqldf('SELECT * FROM datA? EXCEPT SELECT * FROM datB')
#???? Tdate symbol? TA
#1 12/12/12???? WQ B8R
#or
datA[!as.character(with(datA,interaction(Tdate,symbol,TA)))%in%
as.character(with(datB,interaction(Tdate,symbol,TA))),]
#???? Tdate symbol? TA
#3 12/12/12???? WQ B8R
A.K.



----- Original Message -----
From: "Mossadegh, Ramine N." <Ramine.Mossadegh at finra.org>
To: arun <smartpink111 at yahoo.com>
Cc: 
Sent: Monday, May 13, 2013 4:17 PM
Subject: RE: [R] how to merge 2 data frame if you want to exclude mutual obs

Hi Arun,

I am trying to replicate sas code in R.? 

So if in data frame A you have

Tdate? ? ? ? ? ? symbol? ? ? ? TA
12/12/12? ? ? AX? ? ? ? ? ? ?  123
12/11/12? ? ? ZZ? ? ? ? ? ? ? ? A4R
12/12/12? ? ? WQ? ? ? ? ? ? ? B8R

Data frame B
Tdate? ? ? ? ? ? symbol? ? ? ? TA
12/12/12? ? ? AX? ? ? ? ? ? ?  123
12/11/12? ? ? ZZ? ? ? ? ? ? ? ? A4R

I want to end up w/
Tdate? ? ? ? ? ? symbol? ? ? ? TA
12/12/12? ? ? WQ? ? ? ? ? ? ? B8R

All obs not in B

Thanks


-----Original Message-----
From: arun [mailto:smartpink111 at yahoo.com] 
Sent: Monday, May 13, 2013 4:13 PM
To: Mossadegh, Ramine N.
Subject: Re: [R] how to merge 2 data frame if you want to exclude mutual obs

HI,
Please provide a reproducible example and the output you expected.





----- Original Message -----
From: ramoss <ramine.mossadegh at finra.org>
To: r-help at r-project.org
Cc: 
Sent: Monday, May 13, 2013 3:22 PM
Subject: [R] how to merge 2 data frame if you want to exclude mutual obs

In the example below, I am merging 2 data frames & I want everything in the
first one(all)
all2 <- merge(all,spets, by.x=c("tdate","symbol"),
by.y=c("tdate","symbol"),all.x=TRUE)

What if I want to exclude everything in y? I tried below but doesn't seem to
work.
all2 <- merge(all,spets, by.x=c("tdate","symbol"),
by.y=c("tdate","symbol"),all.y=FALSE)

In SAS I? would do:

All2;
? merge all(in=a)
? ? ? ? ? ?? spetz(in=b)
? ? ? ? ? ? ;
by tdate symbol;
if a and not b;
run;

How can I do this in R?
Thanks ahead for your help.



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