[R] Converting nested "for" loops to an "apply" function(s)

[Kurt Newman]

Hello,

I would like to know more about how to use the "apply" family and have attempted to convert nested "for" loops in example code from Contributed Documentation ("The Friendly Beginners' R Course” by Toby Marthews (ZIP, 2007-03-01)") to an "apply" function(s).  The relevant code is:

distances=c(51,65,175,196,197,125,10,56)	#distances of 8 houses from the town centre in m
bearings=c(10,8,210,25,74,128,235,335)	#bearings of the houses in degrees

xpos=distances*sin(bearings*pi/180)		#in sin and cos the argument MUST be in radians
ypos=distances*cos(bearings*pi/180)		

numpoints=length(distances)
nnd=rep(sqrt(2*400*400),times=numpoints)	#start with the maximum possible distance
for (i in 1:numpoints) {	
 for (j in 1:numpoints) {
  if (i!=j) {		
   diffx=abs(xpos[i]-xpos[j])
   diffy=abs(ypos[i]-ypos[j])
   nd=sqrt((diffx^2)+(diffy^2))
   if (nd