```
set.seed(1)
Solder <- factor(sample(c('Thin','Thick'),200,TRUE),c('Thin','Thick'))
Opening <- factor(sample(c('S','M','L'), 200,TRUE),c('S','M','L'))
tab <- table(Opening, Solder)
tab
reShape(tab)
# attach(tab) # do further processing
# An example where a matrix is created from irregular vectors
follow <- data.frame(id=c('a','a','b','b','b','d'),
month=c(1, 2, 1, 2, 3, 2),
cholesterol=c(225,226, 320,319,318, 270))
follow
attach(follow)
reShape(cholesterol, id=id, colvar=month)
detach('follow')
# Could have done :
# reShape(cholesterol, triglyceride=trig, id=id, colvar=month)
# Create a data frame, reshaping a long dataset in which groups are
# formed not just by subject id but by combinations of subject id and
# visit number. Also carry forward a variable that is supposed to be
# constant within subject-visit number combinations. In this example,
# it is not constant, so an arbitrary visit number will be selected.
w <- data.frame(id=c('a','a','a','a','b','b','b','d','d','d'),
visit=c( 1, 1, 2, 2, 1, 1, 2, 2, 2, 2),
k=c('A','A','B','B','C','C','D','E','F','G'),
var=c('x','y','x','y','x','y','y','x','y','z'),
val=1:10)
with(w,
reShape(val, id=data.frame(id,visit),
constant=data.frame(k), colvar=var))
# Get predictions from a regression model for 2 systematically
# varying predictors. Convert the predictions into a matrix, with
# rows corresponding to the predictor having the most values, and
# columns corresponding to the other predictor
# d <- expand.grid(x2=0:1, x1=1:100)
# pred <- predict(fit, d)
# reShape(pred, id=d$x1, colvar=d$x2) # makes 100 x 2 matrix
# Reshape a wide data frame containing multiple variables representing
# repeated measurements (3 repeats on 2 variables; 4 subjects)
set.seed(33)
n <- 4
w <- data.frame(age=rnorm(n, 40, 10),
sex=sample(c('female','male'), n,TRUE),
sbp1=rnorm(n, 120, 15),
sbp2=rnorm(n, 120, 15),
sbp3=rnorm(n, 120, 15),
dbp1=rnorm(n, 80, 15),
dbp2=rnorm(n, 80, 15),
dbp3=rnorm(n, 80, 15), row.names=letters[1:n])
options(digits=3)
w
u <- reShape(w, base=c('sbp','dbp'), reps=3)
u
reShape(w, base=c('sbp','dbp'), reps=3, timevar='week', times=c(0,3,12))
```

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