help() function is Python’s built-in help system, which provides a concise and convenient way to access the documentation (docstrings) of various Python modules, classes, functions, keywords, etc. Whenever you need to understand more about a Python object,
help() can provide a detailed insight into its workings.
Syntax of help()
help() function is incredibly straightforward to use. Its basic syntax is as follows:
When you call
help() with an object as its argument, Python returns the documentation string for that object. If no argument is given,
help() starts the interactive help system.
Interactive Help System
When invoked without any arguments,
help() launches Python’s interactive help utility, which allows users to navigate through the help pages.
You can then type the name of the topic you need help with, and the system will display the relevant information.
How the help() Function Works
help() calls the
pydoc.help() function from the
pydoc module. The
pydoc module automatically generates documentation from Python modules. The help provided by
help() is derived from the docstrings embedded directly in the source code of the Python object in question.
The Role of Docstrings
Docstrings are literal string declarations that are used to document modules, functions, classes, or methods. They should briefly explain the purpose and usage of the code entity they document.
def add(a, b): """Add two numbers and return the result.""" return a + b
"""Add two numbers and return the result.""" is a docstring of the function
Usage Scenarios for help()
help() function can be applied in a variety of scenarios:
Learning Python Modules
Newcomers can use
help() to explore Python standard libraries and third-party modules, learning about various functions, classes, and methods available to them.
Developers can use
help() to understand better the functions or objects they are using, which is particularly useful when debugging code or when using unfamiliar libraries.
When writing new code, programmers can call
help() on classes or functions to quickly remind themselves of the expected parameters, return types, or behavior.
help() is especially useful in the interactive Python shell or in Jupyter notebooks, where developers often need quick access to documentation.
Examples of Using help()
Let’s walk through some practical examples of using the
Getting Help on a Built-in Function
If you want to know more about Python’s built-in
print() function, you can simply call:
Help on built-in function print in module builtins: print(...) print(value, ..., sep=' ', end='\n', file=sys.stdout, flush=False) Prints the values to a stream, or to sys.stdout by default. Optional keyword arguments: file: a file-like object (stream); defaults to the current sys.stdout. sep: string inserted between values, default a space. end: string appended after the last value, default a newline. flush: whether to forcibly flush the stream.
This will display the docstring of
print(), detailing how to use the function and describing its parameters.
Exploring a Module
To explore the functionalities of a Python module, such as
math, you would enter:
import math help(math)
This will return documentation for the entire module, including all functions, classes, and variables defined within.
Understanding a Class
For learning more about a class, especially one that’s part of a framework or library you’re using,
help() can be invaluable. For example:
from datetime import datetime help(datetime)
You will get a detailed description of the
datetime class, its methods, properties, and usages.
Advanced Features of help()
help() is primarily used to access docstrings, it also possesses some advanced features:
You can get help on Python keywords. For instance:
The "if" statement ****************** The "if" statement is used for conditional execution: if_stmt ::= "if" assignment_expression ":" suite ("elif" assignment_expression ":" suite)* ["else" ":" suite] It selects exactly one of the suites by evaluating the expressions one by one until one is found to be true (see section Boolean operations for the definition of true and false); then that suite is executed (and no other part of the "if" statement is executed or evaluated). If all expressions are false, the suite of the "else" clause, if present, is executed. Related help topics: TRUTHVALUE
This command explains the
help() can provide explanations on various topics like “looping”, “exceptions”, and more:
Private and Special Methods
Even private and special methods can be explored using
help(), which can be crucial when delving into the internal workings of a class or module.
Best Practices When Using help()
When utilizing the
help() function, consider the following best practices:
- Write Meaningful Docstrings: The utility of
help()is only as good as the docstrings it’s accessing. Writing clear and concise docstrings for your own modules and functions ensures that
help()becomes an effective tool for others who may use your code.
- Explore Interactively: Use
help()interactively to learn and understand modules and objects in real-time as you work with them.
- Integrate with Development Workflow: Regularly using
help()during development can reduce the need to switch context to web browsers or external documentation, thus maintaining focus and productivity.
Limitations of help()
help() is a powerful tool, it does have its limitations:
- Quality Depends on Docstrings: The value of the information provided by
help()is directly related to the quality of the docstrings in the source code. Poorly documented code will yield less helpful information.
- Not a Substitute for Full Documentation:
help()is not a replacement for comprehensive documentation, especially for complex libraries and frameworks.
- Limited to Python Objects:
help()can only provide information about Python objects. It won’t give you guidance on programming concepts or language fundamentals.
help() function is an integral part of Python’s rich set of introspective features that not only aids in learning and debugging but also promotes a self-documenting code style. Whether you’re a beginner seeking to understand the standard library or an experienced developer working with intricate modules,
help() serves as an immediate, accessible guide.
In an environment where the complexities of software development are ever-increasing,
help() stands out as a built-in companion, a reminder of Python’s philosophy that emphasizes simplicity and accessibility.