Hello,
But
> all.equal(dat1,dat2)
[1] TRUE
So I guess it does have to do with floating-point equality, all.equal
uses .Machine$double.eps. (Which could return FALSE on ocasions we would
expect TRUE, when, for instance, the tolerance could/should be
.Machine$double.eps^0.5.)
Rui Barradas
Em 01-07-2012 18:55, arun escreveu:
HI R help,
I was trying to get identical data frame from a list using two methods.
#Suppose my list is:
listdat1<-list(rnorm(10,20),rep(LETTERS[1:2],5),rep(1:5,2))
#Creating dataframe using cbind
dat1<-data.frame(do.call("cbind",listdat1))
colnames(dat1)<-c("Var1","Var2","Var3")
#Second dataframe conversion
dat2<-data.frame(Var1=listdat1[[1]],Var2=listdat1[[2]],Var3=listdat1[[3]])
#Structure is different in two datasets
>str(dat1)
'data.frame': 10 obs. of 3 variables:
$ Var1: Factor w/ 10 levels "18.6153321029756",..: 5 2 6 8 7 9 1 4 3 10
$ Var2: Factor w/ 2 levels "A","B": 1 2 1 2 1 2 1 2 1 2
$ Var3: Factor w/ 5 levels "1","2","3","4",..: 1 2 3 4 5 1 2 3 4 5
str(dat2)
'data.frame': 10 obs. of 3 variables:
$ Var1: num 20.3 19.2 20.5 20.9 20.5 ...
$ Var2: Factor w/ 2 levels "A","B": 1 2 1 2 1 2 1 2 1 2
$ Var3: int 1 2 3 4 5 1 2 3 4 5
#Converting structure of dat1 to match da2 structure
dat1<-within(dat1,{Var1<-as.numeric(as.character(Var1))
Var3<-as.integer(Var3)})
head(dat1)
Var1 Var2 Var3
1 20.27193 A 1
2 19.17586 B 2
3 20.53197 A 3
4 20.93615 B 4
5 20.53498 A 5
6 21.02044 B 1
head(dat2)
Var1 Var2 Var3
1 20.27193 A 1
2 19.17586 B 2
3 20.53197 A 3
4 20.93615 B 4
5 20.53498 A 5
6 21.02044 B 1
#New structure identical(str(dat1),str(dat2))
'data.frame': 10 obs. of 3 variables:
$ Var1: num 19.9 19 21.2 20.7 20.4 ...
$ Var2: Factor w/ 2 levels "A","B": 1 2 1 2 1 2 1 2 1 2
$ Var3: int 1 2 3 4 5 1 2 3 4 5
'data.frame': 10 obs. of 3 variables:
$ Var1: num 19.9 19 21.2 20.7 20.4 ...
$ Var2: Factor w/ 2 levels "A","B": 1 2 1 2 1 2 1 2 1 2
$ Var3: int 1 2 3 4 5 1 2 3 4 5
[1] TRUE
#structure is identical and dataframe looks to be same, but it is not identical.
identical(dat1,dat2)
[1] FALSE
Is it something to do with the floating point?
Thanks,
A.K.
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