Lua

Removing / Deleting Child Nodes from XML

See more XML Examples

Demonstrates various methods for removing child nodes from an XML document.

The input XML, available at http://www.chilkatsoft.com/data/fruit.xml, is this:

<root>
    <fruit color="red">apple</fruit>
    <fruit color="green">pear</fruit>
    <veg color="orange">carrot</veg>
    <meat animal="cow">beef</meat>
    <xyz>
        <fruit color="blue">blueberry</fruit>
        <veg color="green">broccoli</veg>
    </xyz>
    <fruit color="purple">grape</fruit>
    <cheese color="yellow">cheddar</cheese>
</root>

Lua

local chilkat = require("chilkat")

local xml = chilkat.Xml.new()

-- The sample input XML is available at http://www.chilkatsoft.com/data/fruit.xml
local success = xml:load_xml_file("fruit.xml")
if not success then
    print(xml.last_error_text)
    return
end

-- The RemoveChild method removes (discards) all direct
-- children having the specified tag:
xml:remove_child("fruit")

-- Show the resulting XML:
print("Result with all direct children having a tag equal to \"fruit\" removed:")
print(xml:get_xml())

-- The XML with the "fruit" direct children removed is shown below:
-- Notice that the "fruit" node beneath "xyz" was not removed.
-- This correct because it was not a direct child of the calling node.

-- <root>
--     <veg color="orange">carrot</veg>
--     <meat animal="cow">beef</meat>
--     <xyz>
--         <fruit color="blue">blueberry</fruit>
--         <veg color="green">broccoli</veg>
--     </xyz>
--     <cheese color="yellow">cheddar</cheese>
-- </root>

-- --------------------------------------------------------------------------
-- Restore the original XML:
success = xml:load_xml_file("fruit.xml")

-- The RemoveChildWithContent method removes the child
-- having the exact content specified, regardless of the tag.
-- For example:
xml:remove_child_with_content("pear")

-- Show the resulting XML:
print("Result with the node containing \"pear\" removed:")
print(xml:get_xml())

-- --------------------------------------------------------------------------
-- Restore the original XML:
success = xml:load_xml_file("fruit.xml")

-- The RemoveChildByIndex method removes the Nth direct
-- child.  Indexing begins at 0.  The "xyz" child is at index 4:
xml:remove_child_by_index(4)

-- Show the resulting XML:
-- Notice that the entire "xyz" subtree is removed.
print("Result with the node at index 4 removed:")
print(xml:get_xml())

-- --------------------------------------------------------------------------
-- Restore the original XML:
success = xml:load_xml_file("fruit.xml")

-- Navigate to the node with tag "xyz";
local xyz = xml:find_child("xyz")

-- Remove the "xyz" subtree making it it's own XML document
-- with the "xyz" node at the root:
xyz:remove_from_tree()

-- Show both XML documents:
print(xyz:get_xml())
print(xml:get_xml())

-- Also, the TreeId property is an integer value assigned
-- to nodes in an XML document.  All nodes belonging to
-- the same XML document will have the same TreeId.
-- Notice that the "xyz" node now has a different TreeId:
print("xyz TreeId = " .. xyz.tree_id)
print("xml TreeId = " .. xml.tree_id)