Could you explain me if there is a way to extract outliers from box plot. I have plotted a box plot and I want to extract only the outliers.
Here is the code for the box plot.
# melting down
require(reshape)
melt_nx <- melt(nx, id.vars = c("x", "y"))
boxplot(data = melt_nx, main = "NX", value ~ variable, las = 2,
par(mar = c(15, 5, 4, 2) + 0.1),
names = c("We1", "We2", "we3"))
Is it possible from the box plot to extract the outliers only?
The boxplot function returns a list with one of it node-names as "out". These are the values that are beyond the "whiskers". I don't know about executing par within the argument list but if you want these particular values, then use this:
vals <- boxplot(data = melt_nx, main = "NX", value ~ variable, las = 2,
names = c("We1", "We2", "we3"))
vals$out
And do read all these help pages:
?boxplot
?boxplot.stats
?bxp
?fivenum
I know this has been answered, but for me there is an alternative method using the Boxplot method from the car package. Note the capital B in the Boxplot function call.
This is the code that does it for me, it returns the row numbers of the outliers which you can then use in your dataframe to filter out or extract, etc...
outliers<-Boxplot(x~y, data=df, id.method="y")
Note that the extracted values are of type Character. Then to exclude them you could do something like:
df2 <- df[-as.numeric(outliers),]
Hope this helps a little
Related
My problem is multifaceted.
I would like to plot multiple columns saved in a data frame. Those columns do not have an x variable but would essentially be 1 to 101 consistent for all. I have seen that I can transfer them into long format but most ggplot options require an X. I tried zoo which does what I want it to, but the x-label is all jumbled and I am not aware of how to fix it. (Example of data below, and plot)
df <- zoo(HIP_131_Y0_LC_walk1[1:9])
plot(df)
I have multiple data frames saved in a list so ultimately would like to run a function and apply to all. The zoo function solves step one but I am not able to apply to all the data frames in the list.
graph<-lapply(myfiles,function(x) zoo(x) )
print(graph)
Ideally I would like to also mark minimum and maximum, which I am aware can be done with ggplot but not zoo.
Thank you so much for your help in advance
Assuming that the problem is overlapped panel names there are numerous solutions to this:
abbreviate the names using abbreviate. We show this for plot.zoo and autoplot.zoo .
put the panel name in the upper left. We show this for plot.zoo using a custom panel.
Use a header on each panel. We show this using xyplot.zoo and using ggplot.
The examples below use the test input in the Note at the end. (Next time please provide a complete example including all input in reproducible form.)
The first two examples below abbreviates the panel names and using plot.zoo and autoplot.zoo (which uses ggplot2). The third example uses xyplot.zoo (which uses lattice). This automatically uses headers and is probably the easiest solution.
library(zoo)
plot(z, ylab = abbreviate(names(z), 8))
library(ggplot2)
zz <- setNames(z, abbreviate(names(z), 8))
autoplot(zz)
library (lattice)
xyplot(z)
(click on plots to see expanded; continued after plots)
This fourth example puts the panel names in the upper left of the panel themselves using plot.zoo with a custom panel.
pnl <- function(x, y, ..., pf = parent.frame()) {
legend("topleft", names(z)[pf$panel.number], bty = "n", inset = -0.1)
lines(x, y)
}
plot(z, panel = pnl, ylab = "")
(click on plot to see it expanded)
We can also get headers with autoplot.zoo similar to in lattice above.
library(ggplot2)
autoplot(z, facets = ~ Series, col = I("black")) +
theme(legend.position = "none")
(click to expand; continued after graphics)
List
If you have a list of vectors L (see Note at end for a reproducible example of such a list) then this will produce a zoo object:
do.call("merge", lapply(L, zoo))
Note
Test input used above.
library(zoo)
set.seed(123)
nms <- paste0(head(state.name, 9), "XYZ") # long names
m <- matrix(rnorm(101*9), 101, dimnames = list(NULL, nms))
z <- zoo(m)
L <- split(m, col(m)) # test list using m in Note
I created an object of class cca in vegan and now I am trying to tidy up the triplot. However, I seemingly can't use the select argument to only show specified items.
My code looks like this:
data("varechem")
data("varespec")
ord <- cca(varespec ~ Al+S, varechem)
plot(ord, type = "n")
text(ord, display = "sites", select = c("18", "21"))
I want only the two specified sites (18 and 21) to appear in the plot, but when I run the code nothing happens. I do not even get an error meassage.
I'm really stuck, but I am fairly certain that this bit of code is correct. Can someone help me?
I can't recall now, but I don't think the intention was to allow "names" to select which rows of the scores should be selected. The documentation speaks of select being a logical vector, or indices of the scores to be selected. By indices it was meant numeric indices, not rownames.
The example fails because select is also used to subset the labels character vector of values to be plotted in text(), and this labels character vector is not named. Using a character vector to subset another vector requires that the other vector be named.
Your example works if you do:
data("varechem")
data("varespec")
ord <- cca(varespec ~ Al + S, varechem)
plot(ord, type = "n")
take <- which(rownames(varechem) %in% c("18", "21"))
# or
# take <- rownames(varechem) %in% c("18", "21")
text(ord, display = "sites", select = take)
I'll have a think about whether it will be simple to support the use case of your example.
The following code probably gives the result you want to achieve:
First, create an object to store the blank CCA1-CCA2 plot
p1 = plot(ord, type = "n")
Find and then save the coordinates of the sites 18 and 21
p1$p1$sites[c("18", "21"),]
# CCA1 CCA2
#18 0.3496725 -1.334061
#21 -0.8617759 -1.588855
site18 = p1$sites["18",]
site21 = p1$sites["21",]
Overlay the blank CCA1-CCA2 plot with the points of site 18 and 21. Setting different colors to different points might be a good idea.
points(p1$sites[c("18", "21"),], pch = 19, col = c("blue", "red"))
Showing labels might be informative.
text(x = site18[1], y = site18[2] + 0.3, labels = "site 18")
text(x = site21[1], y = site21[2] + 0.3, labels = "site 21")
Here is the resulted plot.
I am running quantile regressions for several independent variables separately (same dependent). I want to plot only the slope estimates over several quantiles of each variable in a single plot.
Here's a toy data:
set.seed(1988)
y <- rnorm(50, 5, 3)
x1 <- rnorm(50, 3, 1)
x2 <- rnorm(50, 1, 0.5)
# Running Quantile Regression
require(quantreg)
fit1 <- summary(rq(y~x1, tau=1:9/10), se="boot")
fit2 <- summary(rq(y~x2, tau=1:9/10), se="boot")
I want to plot only the slope estimates over quantiles. Hence, I am giving parm=2 in plot.
plot(fit1, parm=2)
plot(fit2, parm=2)
Now, I want to combine both these plots in a single page.
What I have tried so far;
I tried setting par(mfrow=c(2,2)) and plotting them. But it's producing a blank page.
I have tried using gridExtra and gridGraphics without success. Tried to convert base graphs into Grob objects as stated here
Tried using function layout function as in this document
I am trying to look into the source code of plot.rqs. But I am unable to understand how it's plotting confidence bands (I'm able to plot only the coefficients over quantiles) or to change mfrow parameter there.
Can anybody point out where am I going wrong? Should I look into the source code of plot.rqs and change any parameters there?
While quantreg::plot.summary.rqs has an mfrow parameter, it uses it to override par('mfrow') so as to facet over parm values, which is not what you want to do.
One alternative is to parse the objects and plot manually. You can pull the tau values and coefficient matrix out of fit1 and fit2, which are just lists of values for each tau, so in tidyverse grammar,
library(tidyverse)
c(fit1, fit2) %>% # concatenate lists, flattening to one level
# iterate over list and rbind to data.frame
map_dfr(~cbind(tau = .x[['tau']], # from each list element, cbind the tau...
coef(.x) %>% # ...and the coefficient matrix,
data.frame(check.names = TRUE) %>% # cleaned a little
rownames_to_column('term'))) %>%
filter(term != '(Intercept)') %>% # drop intercept rows
# initialize plot and map variables to aesthetics (positions)
ggplot(aes(x = tau, y = Value,
ymin = Value - Std..Error,
ymax = Value + Std..Error)) +
geom_ribbon(alpha = 0.5) +
geom_line(color = 'blue') +
facet_wrap(~term, nrow = 2) # make a plot for each value of `term`
Pull more out of the objects if you like, add the horizontal lines of the original, and otherwise go wild.
Another option is to use magick to capture the original images (or save them with any device and reread them) and manually combine them:
library(magick)
plots <- image_graph(height = 300) # graphics device to capture plots in image stack
plot(fit1, parm = 2)
plot(fit2, parm = 2)
dev.off()
im1 <- image_append(plots, stack = TRUE) # attach images in stack top to bottom
image_write(im1, 'rq.png')
The function plot used by quantreg package has it's own mfrow parameter. If you do not specify it, it enforces some option which it chooses on it's own (and thus overrides your par(mfrow = c(2,2)).
Using the mfrow parameter within plot.rqs:
# make one plot, change the layout
plot(fit1, parm = 2, mfrow = c(2,1))
# add a new plot
par(new = TRUE)
# create a second plot
plot(fit2, parm = 2, mfrow = c(2,1))
I'm plotting some Q-Q plots using the qqplot function. It's very convenient to use, except that I want to color the data points based on their IDs. For example:
library(qualityTools)
n=(rnorm(n=500, m=1, sd=1) )
id=c(rep(1,250),rep(2,250))
myData=data.frame(x=n,y=id)
qqPlot(myData$x, "normal",confbounds = FALSE)
So the plot looks like:
I need to color the dots based on their "id" values, for example blue for the ones with id=1, and red for the ones with id=2. I would greatly appreciate your help.
You can try setting col = myData$y. I'm not sure how the qqPlot function works from that package, but if you're not stuck with using that function, you can do this in base R.
Using base R functions, it would look something like this:
# The example data, as generated in the question
n <- rnorm(n=500, m=1, sd=1)
id <- c(rep(1,250), rep(2,250))
myData <- data.frame(x=n,y=id)
# The plot
qqnorm(myData$x, col = myData$y)
qqline(myData$x, lty = 2)
Not sure how helpful the colors will be due to the overplotting in this particular example.
Not used qqPlot before, but it you want to use it, there is a way to achieve what you want. It looks like the function invisibly passes back the data used in the plot. That means we can do something like this:
# Use qqPlot - it generates a graph, but ignore that for now
plotData <- qqPlot(myData$x, "normal",confbounds = FALSE, col = sample(colors(), nrow(myData)))
# Given that you have the data generated, you can create your own plot instead ...
with(plotData, {
plot(x, y, col = ifelse(id == 1, "red", "blue"))
abline(int, slope)
})
Hope that helps.
I'am trying to print a plot, depending on a variable with 12 terms. This plot is the result of cluster classification on sequences, using OM distance.
I print this plot on one pdf page :
pdf("YYY.pdf", height=11,width=20)
seqIplot(XXX.seq, group=XXX$variable, cex.legend = 2, cex.plot = 1.5, border = NA, sortv =XXX.om)
dev.off()
But the printing is to small ... so i try to print this on 2 pages, like this :
pdf("YYY.pdf", height=11,width=20)
seqIplot(XXX.seq, group=XXX$variable, variable="1":"6", cex.legend = 2, cex.plot = 1.5, border = NA, sortv =XXX.om)
seqIplot(XXX.seq, group=XXX$variable, variable="7":"12", cex.legend = 2, cex.plot = 1.5, border = NA, sortv = XXX.om)
dev.off()
But it doesn't work ... Do you know how I can ask R to separate terms' variables into two groups, so as to print 6 graphics per pdf page ?
The solution is to plot separately the subset of groups you want on each page. Here is an example using the biofam data provided by TraMineR. The group variable p02r04 is religious participation which takes 10 different values.
library(TraMineR)
data(biofam)
bs <- seqdef(biofam[,10:25])
group <- factor(biofam$p02r04)
lv <- levels(group)
sel <- (group %in% lv[1:6])
seqIplot(bs[sel,], group=group[sel], sortv="from.end", withlegend=FALSE)
seqIplot(bs[!sel,], group=group[!sel], sortv="from.end")
If you are sorting the index plot with a variable you should indeed take the same subset of the sort variable, e.g. sortv=XXX.om[sel] in your case.
I don't know if I understood your question, you could post some data in order to help us reproduce what you want, maybe this helps. To plot six graphs in one page you should adjust the mfrow parameter, is that what you wanted?
pdf("test.pdf")
par(mfrow=c(3,2))
plot(1:10, 21:30)
plot(1:10, 21:30, pch=20)
hist(rnorm(1000))
barplot(VADeaths)
...
dev.off()