method
<<
<<(p1)
public
Append—Pushes the given object on to the end of this array. This expression returns the array itself, so several appends may be chained together.
a = [ 1, 2 ] a << "c" << "d" << [ 3, 4 ] #=> [ 1, 2, "c", "d", [ 3, 4 ] ] a #=> [ 1, 2, "c", "d", [ 3, 4 ] ]