Update r.html.markdown

Added logical operators that were missing.

r.html.markdown

@@ -229,6 +229,13 @@ FALSE != FALSE	# FALSE
 FALSE != TRUE	# TRUE
 # Missing data (NA) is logical, too
 class(NA)	# "logical"
+# Use for | and & for logic operations.
+# OR
+TRUE | FALSE	# TRUE
+# AND
+TRUE & FALSE	# FALSE
+# You can test if x is TRUE
+isTRUE(TRUE)	# TRUE
 # Here we get a logical vector with many elements:
 c('Z', 'o', 'r', 'r', 'o') == "Zorro" # FALSE FALSE FALSE FALSE FALSE
 c('Z', 'o', 'r', 'r', 'o') == "Z" # TRUE FALSE FALSE FALSE FALSE