Python's help() function provides interactive and flexible ways to explore documentation within the interpreter. It displays docstrings for objects, allowing you to examine modules, classes, functions, and methods. Beyond basic usage, help() offers several features like searching for specific terms within documentation, navigating related entries through hyperlinks (if your pager supports it), and viewing the source code of Python objects when available. It utilizes the pydoc module and works on live objects, not just names, reflecting runtime modifications like monkey-patching. While powerful, help() is best for interactive exploration and less suited for programmatic documentation access where inspect or pydoc modules provide better alternatives.
The Python help() function is a powerful built-in tool for accessing documentation and understanding objects within a Python session. It provides a rich, interactive way to explore modules, classes, functions, and other Python components. Its functionality extends beyond simply displaying docstrings; it offers several key features that enhance the learning and debugging process.
One of its primary functions is displaying docstrings. When invoked on an object, help() presents the associated docstring, which is a string literal used to document the object's purpose, usage, and parameters. This allows developers to quickly access essential information about how to use a specific piece of code.
Beyond just showing docstrings, help() provides interactive exploration capabilities. Once invoked, it enters an interactive help mode. Within this mode, users can navigate related documentation using various commands. For example, typing the name of a class member within the help prompt will display its corresponding docstring. This interactive nature allows developers to delve deeper into the structure and functionality of complex objects without leaving their current coding environment. Users can effectively "browse" the documentation by typing in keywords or names.
The help() function is also capable of providing assistance on specific topics. Instead of providing an object, a user can directly input keywords or topics into the help() function, such as help("modules"). This lists all available modules, offering a high-level overview of the Python environment and available libraries. This feature assists in discovering available functionalities and exploring various parts of the standard library and any installed third-party packages.
Furthermore, help() leverages the pydoc module to generate its output. This integration means it can access and display information from various sources, enhancing the breadth and depth of the provided help. It's not limited to just inspecting currently loaded objects, but can reach into the wider installed Python environment for information.
Finally, while primarily used interactively within a REPL or Python interpreter, help() can also be incorporated into programs. This allows developers to programmatically access and process help information, potentially building custom documentation utilities or integrating help features directly into their applications. This programmatic access provides opportunities for more advanced uses beyond interactive exploration.
Summary of Comments ( 30 )
https://news.ycombinator.com/item?id=43266546
Hacker News users discussed the nuances and limitations of Python's
help()function. Some found it useful for quick checks, especially for built-in functions, while others pointed out its shortcomings when dealing with more complex objects or third-party libraries, where docstrings are often incomplete or missing. The discussion touched upon the superiority of usingdir()in conjunction withhelp(), the value of IPython's?operator for introspection, and the frequent necessity of resorting to external documentation or source code. One commenter highlighted the awkwardness ofhelp()requiring an object rather than a name, and another suggested thepydocmodule or online documentation as more robust alternatives for exploration and learning. Several comments also emphasized the importance of well-written docstrings and recommended tools like Sphinx for generating documentation.The Hacker News post titled "The features of Python's help() function," linking to a Python Morsels article about the same, generated a modest discussion with several interesting points raised.
One commenter questioned the article's assertion that
help()is rarely used, arguing that it's invaluable, especially for exploring third-party libraries within an interactive session. They specifically highlighted its usefulness when needing a quick reminder of a function's signature or available methods on an object without resorting to external documentation.Another commenter pointed out that the use of
help()is often superseded by IDE features like autocompletion and integrated documentation lookup. While acknowledginghelp()'s utility in certain situations, especially environments lacking robust IDE support, they felt modern tooling made it less essential.Building on the IDE theme, another user emphasized the efficiency of using "type hinting + mypy + IDE feature" as a superior approach to relying on
help(). This combination allows for static analysis and real-time feedback within the code editor, catching potential issues before runtime. However, this was countered by another commenter who suggested that help was useful for more ad hoc or interactive cases that wouldn't be well served by typehints.A different commenter provided a concise practical tip: wrapping an expression in parentheses allows using
help()directly on it without assignment to a variable. This allows for quick checks of documentation without interrupting the flow of coding. This is contrasted with assigning the value of an expression to a variable, then callinghelp()using the name of that variable.One commenter mentioned the IPython shell's enhanced
?operator as a preferred alternative tohelp(). They noted its ability to display source code and other useful information beyond the standard docstrings. They suggested binding the standardhelp()function to?in regular Python REPLs.Finally, one commenter expressed a strong preference for
dir()overhelp(). They find it more efficient for quickly listing available attributes and methods. While acknowledging the usefulness of docstrings accessible throughhelp(), they prioritize the rapid overview provided bydir().