66 lines
2.7 KiB
Markdown
66 lines
2.7 KiB
Markdown
---
|
|
title: Docstring
|
|
---
|
|
## Docstring
|
|
|
|
Docstring is a way for developers to communicate the purpose, parameters, requirements, and usage of a function in Python to other developers. It allows for ease of code maintenance and understanding.
|
|
|
|
Unlike conventional source code comments the docstring should describe what the
|
|
function does, not how.
|
|
|
|
A similar example to Docstring is @Javadoc in Java.
|
|
|
|
Docstring is written as a multi-line comment just after the declaration header in Python. There are 4 different parts to a docstring:
|
|
|
|
1. Type of input, and type of output
|
|
* Input/output can be ```obj, list, bool, int, str, float```
|
|
2. Description of function
|
|
* Brief, but thorough description of what your function does
|
|
3. Requirements
|
|
* This is read by a human, so it does not have to be code
|
|
4. Test cases (normally 2-3)
|
|
|
|
The general format is listed below.
|
|
|
|
## Format of Docstring
|
|
|
|
```python
|
|
def my_examplefunc(input_type1, input_type2):
|
|
'''(input_type1, input_type2) -> output_type # Your first line will be the input/output. Remember the space around the arrow!
|
|
Here is a description of my example function # Your second line will be the description
|
|
REQ: type(input_type1) == list # Your next line (or lines) will be the requirements for the input of your function
|
|
REQ: type(input_type2) == str
|
|
>>> my_example_func([2, 3], "Hello World!") # After the requirements come test cases
|
|
[2, 3] "Hello World"
|
|
>>> my_example_func([7, 2], "Another test case") # Your first line of the test case is an example of the usage, prefaced by >>>
|
|
[7, 2] "Another test case" # Your second line of the test case is the output
|
|
>>> my_example_func([5, 6], "Last test case")
|
|
[5, 6] "Last test case"
|
|
'''
|
|
# Your code goes here, underneath the Docstring
|
|
```
|
|
|
|
Docstring is best understood with examples, so take a look at the below example program where the program outputs True if a number is less than 5, and False if a number is greater than 5.
|
|
|
|
## Example 1
|
|
```python
|
|
def is_less_than_five(some_number):
|
|
'''(int) -> bool
|
|
Returns True if the given number is less than 5, and False is the given number is greater than 5.
|
|
REQ: some_number != 5
|
|
>>> is_less_than_five(4)
|
|
True
|
|
>>> is_less_than_five(6)
|
|
False
|
|
>>> is_less_than_five(100000)
|
|
False
|
|
'''
|
|
# Your code goes here
|
|
```
|
|
|
|
### Some useful links:
|
|
Numpy and Google Docstrings are two commonly used approaches:
|
|
* Google: http://sphinxcontrib-napoleon.readthedocs.io/en/latest/example_google.html
|
|
* Numpy: http://sphinxcontrib-napoleon.readthedocs.io/en/latest/example_numpy.html
|
|
Also, refer to some good old PEP commentary: https://www.python.org/dev/peps/pep-0257/
|