Advanced XPath

Transcript

1. Learning Together Advanced XPath & Tritium
2. As You Know, XPath lets you treat the DOM as a TREE
3. This allows us to move around the tree in a given context. If we know our current node, we can utilize that to tell use information about parents, siblings, and even children.
4. The name of the tool to do this are collectively called XPath Axes
5. You Use Them Like this: axisname::node[thathas]
6. Let’s See them in Action!
7. ancestor::*
8. ancestor::* Look up the tree from the starting node at the parents, grandparents, etc. and check them against the following Xpath.
9. Example: http://tester.tritium.io/a6ada7f98f283432e0a3dd92b05084967b271272
10. self::*
11. self::* Selects the current node. This is useful for selecting the current node only if a given set of criteria are true.
12. Example: http://tester.tritium.io/facd7926fa351eef2453ad7af052c94eb6771d21
13. following-sibling::* preceding-sibling::*
14. following-sibling::* preceding-sibling::* Indicates all the nodes that have the same parent as the context node and appear after/ before the context node in the source document.
15. Example: http://tester.tritium.io/2e5c2cb2207f8f1e46358c441d6fbfa6a8354c8c
16. descendant-or-self::*
17. descendant-or-self::* Indicates the context node and all of its descendants. Mostly useful for applying transformations in bulk.
18. Example: http://tester.tritium.io/ac3f5e0b6103ef41d8ba5360c46e101248edb822
19. Nested Selectors
20. A nested selector allows you to select a node based on its children
21. It looks something like this: ./div[@class='parent' and ./li[@class='other-class']]
22. Any Valid XPath is allowed to be nested in an [that- has] expression.
23. Try it out: http://tester.tritium.io/26fb89058fbc28cb7ccd91f90aee3ef2e42127dd
24. XPath functions
25. XPath has a number of functions that can be applied to a selector to ensure you are selecting the correct node.
26. The most commonly used are: not(), count(), contains(), and last()
27. A function performs an action that can affect a selector.
28. not(input) Selects if the input is not true count(selector) Counts the number of the given selector last() True if the node is the last node in the selector contains(attribute, string) True if the attribute has the string in it.
29. Example: http://tester.tritium.io/d105fbd4b87948913cd3853575fa6a6d1cfec9e5
30. Q & A