Displaying 2 results from an estimated 2 matches for "firstdiff".
2009 Aug 04
2
Caculate first difference from a dataframe; write a simulation
...###############################
##Question1:I want to calculate the first difference of mydat4[,1:2]
t<-diff(mydat4[,1:2],1)
#The command fails, why? Because it fails I've written a code for calculating the first diff
c<-dim(mydat4)
e<-mydat4[-c[1],]
dim(e)
f<-mydat4[-1,]
dim(f)
#f
firstDiff<-data.frame(f[,-c(3:4)]-e[,-c(3:4)])
# Draw a random sample for the first differences
d<-dim(mydat3)
z<-mydat3[d[1],1:2]
z.t<-t(z)
x<-data.frame(t(firstDiff[,1:2]))
y<-sample(x[,1:2],1,replace=T)
ad<-z.t+y
##Output of ad is given below
ad
X6
Level 5.04
spread 0.25
##...
2009 Aug 05
1
writing a simulation
...t3[[1]],q,include.lowest=T)
summary(z.level)
q<-quantile(mydat3[[2]],c(0,0.25,0.75,1))
z.shape<-cut(mydat3[[2]],q,include.lowest=T)
summary(z.shape)
table(z.shape,z.level)
mydat3$State<-as.numeric(interaction(z.shape,z.level,sep=""))
#the clue on interaction was a great help
firstDiff<-data.frame(apply(mydat3[,1:2],2,diff))
# the clue of using apply to use diff was very helpful
#################################################################################
# Draw a random sample for the differences
d<-dim(mydat3)
z<-mydat3[d[1],1:2]
z.t<-t(z)
x<-data.frame(t(f...