Hello,
Inline
Em 31-07-2012 02:59, Wellington Silva escreveu:
Ok,
This really helped.
You've probably noticed, I'm a begginer using R.
And when you said that you tried with rnorm and the counts were not zero,
where did you use the rnorm?
Where the runif is, in its stead use
matrix( rnorm(nc*dds), ...etc... )
But note that this is fake data, what is the distribution of your
dataset? Or is the purpose of this simulations? If so, there must also
be a distribution to replicate, no?
Rui Barradas
The point is, I need this count to be different from zero, so I can use the
ARL later on.
I need how many values are out of control (for each column /variable),
store these values in a vector, calculate this vector's mean, and then
calculate the ARL.
I've got to the same point as you did, but I'm stuck in the same problem. I
need this count do be different from zero.
I'm still learning, haha, please be patient.
Best Regards.
2012/7/30 Rui Barradas <ruipbarra...@sapo.pt>
Hello,
Try the following.
# make up some data
dds <- 1e3
nc <- 10
xss <- data.frame(matrix(runif(nc***dds, min=-1, max=1), ncol=nc))
names(xss) <- paste0("xs", 1:10)
# two functions with descriptive names
getControlLimits <- function(x, L = 3){
mu <- mean(x)
sigma <- sd(x)
c(lcl = mu - L*sigma, ucl = mu + L*sigma)
}
countOutOfControl <- function(x, L = 3){
cl <- getControlLimits(x, L = L)
sum( x < cl["lcl"] | x > cl["ucl"] )
}
sapply(xss, getControlLimits) # To know why the next returns all zeros
sapply(xss, countOutOfControl) # No values outside control limits
The data comes from an uniform in the interval (-1, 1) therefore the sd is
sqrt(1/3) = 0.577. Times 3 gives values for lcl and ucl clearly below and
above -1 and 1, respectively. (I've tried rnorm and the counts were not
zero.)
But this is just a data example to see if the code works, and it does.
Hope this helps,
Rui Barradas
Em 30-07-2012 22:04, Wellington Silva escreveu:
Ok Rui,
I'll try to explain myself a little bit better.
I have 10 columns, with 1000 rows each. (Each column represents a variable
of the process)
these columns were simulated using runif, with values between 4 and 6.
I need to calculate the control limits for each column (variable), and
verify if they are within the bounds accepted.
For now, I'm reading these columns separately, I'm creating variables to
read only one of the each column, and then check if the values in this
column is within the limits or not.
PS. All these columns originally come from a dataframe. something like
this: (dds = 1000)
xs1<-runif(dds, min=-1, max=1)
xs2<-runif(dds, min=-1, max=1)
xs3<-runif(dds, min=-1, max=1)
xs4<-runif(dds, min=-1, max=1)
xs5<-runif(dds, min=-1, max=1)
...
xs10<-runif(dds, min=-1,max=1)
xs<-data.frame(xs1,xs2,xs3,**xs4,xs5,..xs10)
______________________________**_______________
#Reading columns (first one)
c.n1 <- 'xs1'
c1 <- with(xss, get(c.n1))
#Mean
mc1 <- mean (c1)
#Standard deviation
sdc1 <- sd(c1)
#Control Limits
L=3
uclc1 = mc1 + L*sdc1
lclc1 = mc1 - L*sdc1
I need an "if" inside a loop to do the following:
for (each column)
if (value in c1 < lclc1 | value in c1 > uclc1) {Count how many values are
outside the bounds}
And I need this process to be repeated to all columns.
2012/7/30 Rui Barradas <ruipbarra...@sapo.pt>
Hello,
Your code example doesn't make much sense, it needs decrypting. Let's
see,
for(k in 1:length(c1)){
if(c1[k] < lcl | c1[k] > ucl) {do something}
}
If this is it, then you can completely avoid the loop:
i1 <- c1 < lcl | c1 > ucl # create an index vector
out.of.control <- c1[ i1 ] # save the values
When you say you have a column, is it a matrix column? data.frame?
Give a data example with
dput( head(myData, 20) ) # paste the output of this in a post
Hope this helps,
Rui Barradas
Em 29-07-2012 21:59, Wellington G. Silva escreveu:
Hi,
I'm Wellington from Brazil and I have the following issue:
I've been working on a project a for a while, and I'm having trouble in
using the loop (for)
I need to read a column (c1), and for each value of this column, I need
to
check if it's within the control limits
So, I was trying to do this:
For (k in 1: c1)
If (c1< lcl1 | c1 > ucl1) {here I need to store the values outside the
limits)
I have 5 columns, need to do the same process in each one of them.
And later on I'm gonna concatenate these 5 vectors and calculate its
mean
for an ARL project.
[[alternative HTML version deleted]]
______________________________****________________
R-help@r-project.org mailing list
https://stat.ethz.ch/mailman/****listinfo/r-help<https://stat.ethz.ch/mailman/**listinfo/r-help>
<https://stat.**ethz.ch/mailman/listinfo/r-**help<https://stat.ethz.ch/mailman/listinfo/r-help>
PLEASE do read the posting guide http://www.R-project.org/**
posting-guide.html
<http://www.R-project.org/**posting-guide.html<http://www.R-project.org/posting-guide.html>
and provide commented, minimal, self-contained, reproducible code.
______________________________________________
R-help@r-project.org mailing list
https://stat.ethz.ch/mailman/listinfo/r-help
PLEASE do read the posting guide http://www.R-project.org/posting-guide.html
and provide commented, minimal, self-contained, reproducible code.
