ifelse()

I have a problem with ifelse(), I do not understand how it works. 

X<-c(2,2,1,1,0,0)
str(X)

 num [1:6] 2 2 1 1 0 0

Y<-ifelse(X>0,1,0)
Y

[1] 1 1 1 1 0 0

Can some one explain what is going on, I do not understand what ifelse is
doing in this case. Can someone explain the output Y.

ifelse evaluates the condition given in its first argument and returns
the value of the second argument for all cases found to be TRUE and
the value of the third argument otherwise. As the first 4 elments of X
fulfill your condition (X>0) the corresponding result for them is 1 and
the rest 0.

See ?ifelse for details.

cu
	Philipp

Dr. Philipp Pagel
Lehrstuhl f?r Genomorientierte Bioinformatik
Technische Universit?t M?nchen
Wissenschaftszentrum Weihenstephan
85350 Freising, Germany
http://mips.gsf.de/staff/pagel