[R] Conditional ploting with logical vector

Armin Goralczyk agoralczyk at gmail.com
Sat Apr 5 12:25:58 CEST 2008

Hi list
Maybe someone can help with the following problem (thanks in advance):

In a function I have a plot and want to add symbols/text only when
indicated by a logical vector (which was generated by the function
before, not manually like in the following example):

plot(1:10, 1:10)
lv <- c(T,T,T,F,F,F,T,T,T,F)
text(1:10, 1:10, '*', pos = 3)

In this example the asterisk is plotted at every yx-coordinate
indicated. How Can I make it appear only when 'TRUE' in the lv?

Another (statistical) question:
Actually this function generates significance levels to the plot at 10
time points of a time series by comparing the values at the single
time points by a t-test. I know this is probably not the correct way
to compare the whole series, but I have to do it this way
('constraints'). The question is: do I have to adjust for multiple
testing by e.g. Bonferroni correction?

Armin Goralczyk, M.D.
Universitätsmedizin Göttingen
Abteilung Allgemein- und Viszeralchirurgie
Rudolf-Koch-Str. 40
39099 Göttingen
Dept. of General Surgery
University of Göttingen
Göttingen, Germany

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