Append the item {expr} to List or Blob {object}. Returns the resulting List or Blob. Examples:

:let alist = add([1, 2, 3], item)
:call add(mylist, "woodstock")

Note that when {expr} is a List it is appended as a single item. Use extend() to concatenate Lists. When {object} is a Blob then {expr} must be a number. Use insert() to add an item at another position. Returns 1 if {object} is not a List or a Blob.

Can also be used as a method:

mylist->add(val1)->add(val2)