when should you use documentation strings instead of hash-mark comments name three ways you can view documentation strings how can you obtain list of the available attributes in an object how can you get list of all available modules on your computer which python book should you purchase after this onetest your knowledgeanswers documentation strings (docstringsare considered best for largerfunctional documentationdescribing the use of modulesfunctionsclassesand methods in your code hash-mark comments are today best limited to smaller-scale documentation about arcane expressions or statements at strategic points on your code this is partly because docstrings are easier to find in source filebut also because they can be extracted and displayed by the pydoc system you can see docstrings by printing an object' __doc__ attributeby passing it to pydoc' help functionand by selecting modules in pydoc' html-based user interfaces--either the - gui client mode in python and earlieror the - allbrowser mode in python and later (and required as of both run clientserver system that displays documentation in popped-up web browser pydoc can also be run to save module' documentation in an html file for later viewing or printing the built-in dir(xfunction returns list of all the attributes attached to any object list comprehension of the form [ for in dir(xif not starts with('__')can be used to filter out internals names with underscores (we'll learn how to wrap this in function in the next part of the book to make it easier to use in python and earlieryou can run the pydoc gui interfaceand select "open browser"this opens web page containing link to every module available to your programs this gui mode no longer works as of python in python and lateryou get the same functionality by running pydoc' newer all-browser mode with - command-line switchthe top-level start page displayed in web browser in this newer mode has the same index page listing all available modules mineof course (seriouslythere are hundreds todaythe preface lists few recommended follow-up booksboth for reference and for application tutorialsand you should browse for books that fit your needs the documentation interlude