parsel vs. python-sql vs. waiting vs. zope.interface Comparison Chart

Parsel is a BSD-licensed Python library to extract and remove data from HTML and XML using XPath and CSS selectors, optionally combined with regular expressions. Create a selector object for the HTML or XML text that you want to parse. Then use CSS or XPath expressions to select elements. CSS is a language for applying styles to HTML documents. It defines selectors to associate those styles with specific HTML elements. XPath is a language for selecting nodes in XML documents, which can also be used with HTML. You can use either CSS or XPath. CSS is usually more readable, but some things can only be done with XPath. Being built atop lxml, parsel selectors support some EXSLT extensions and come with pre-registered namespaces to use in XPath expressions. Parsel selectors allow you to chain selectors, so most of the time you can just select by class using CSS and then switch to XPath when needed.

waiting is a small library for waiting for stuff to happen. It basically waits for a function to return True, in various modes. Waiting is compatible with flux for simulated timelines. The most basic usage is when you have a function you want to wait for. Waiting forever is very simple. If your predicate returns a value, it will be returned as the result of wait(). A timeout parameter can also be specified. When a timeout expires without the predicate being fulfilled, an exception is thrown. Sleeping polls the predicate at a certain interval (by default 1 second). The interval can be changed with the sleep_seconds argument. When waiting for multiple predicates, waiting provides two simple facilities to help aggregate them, any and all. They resemble Python’s built-in any() and all(), except that they don’t call a predicate once it has been satisfied (this is useful when the predicates are inefficient and take time to complete).