[R] If(cond) statement

[Beck, Kenneth (STP)]

Why will this simple statement not work? I think I am following the
documentation for if(cond) statements, and I have tried wrapping the
cons.expr and alt.expr in {}, I get the same error. There is no example
in the help file, and this is not covered in the Introduction to R,
SimpleR or other tutorials I have looked into.

mxx=max(cpx_list$nMV);
mxy=max(trend_list$nMV);
if (mxx>mxy)
  mxy=mxx
else
  mxx=mxy

Error: unexpected 'else' in "else"

Why does this error message have the first 'else' in single quote and
second in double??