From b98ec97a0787be229d18155bc78a106ea490ecb3 Mon Sep 17 00:00:00 2001 From: medusa Date: Wed, 6 Mar 2024 03:32:44 +0000 Subject: [PATCH] Add docs/tech_docs/advanced_python.md --- docs/tech_docs/advanced_python.md | 81 +++++++++++++++++++++++++++++++ 1 file changed, 81 insertions(+) create mode 100644 docs/tech_docs/advanced_python.md diff --git a/docs/tech_docs/advanced_python.md b/docs/tech_docs/advanced_python.md new file mode 100644 index 0000000..9f2aaa2 --- /dev/null +++ b/docs/tech_docs/advanced_python.md @@ -0,0 +1,81 @@ +For an advanced programmer new to Python, understanding Python's unique idioms, "Pythonic" ways, and potential gotchas is essential to write efficient, readable, and Pythonic code. Here's a compiled list of Pythonisms, idioms, and gotchas to look out for: + +### Pythonisms and Idioms + +1. **List Comprehensions**: Compact way to process all or part of the elements in a sequence and return a list with the results. + ```python + squares = [x**2 for x in range(10)] + ``` + +2. **Dictionary Comprehensions**: Similar to list comprehensions but for dictionaries. + ```python + square_dict = {x: x**2 for x in range(10)} + ``` + +3. **Using Underscore for Unused Variables**: It's a Pythonic way to indicate that a variable is intentionally unused. + ```python + for _ in range(10): + do_something() + ``` + +4. **Unpacking**: A way to unpack values from a sequence or iterable into variables. + ```python + a, b, *rest = range(10) + ``` + +5. **The Zen of Python**: Accessible by typing `import this`, it's a collection of Python's design principles. + +6. **Using `enumerate()` for Loops**: To get both the index and the value of an item in a list. + ```python + for index, value in enumerate(my_list): + print(index, value) + ``` + +7. **Function Arguments**: Python supports default, keyword, positional, and arbitrary arguments. + ```python + def func(a, b, c=5, *args, **kwargs): + pass + ``` + +8. **The Walrus Operator (`:=`)**: Introduced in Python 3.8, allows you to assign values to variables as part of an expression. + ```python + if (n := len(a)) > 10: + print(f"List is too long ({n} elements)") + ``` + +### Gotchas + +1. **Mutable Default Arguments**: Default argument values are evaluated only once at function definition time, which means that modifying a default argument will affect all subsequent calls to the function. + ```python + def append_to(element, to=[]): + to.append(element) + return to + ``` + +2. **Dynamic Typing**: While flexible, it can lead to unexpected behaviors if not carefully managed, especially when coming from statically-typed languages. + +3. **Indentation**: Python uses indentation to define blocks, making code readability a part of the syntax. However, incorrect indentation can lead to `IndentationError` or unexpected behavior. + +4. **`==` vs `is`**: `==` checks for equality, while `is` checks for identity. This distinction is crucial for understanding mutable and immutable objects. + ```python + a = [1, 2, 3] + b = a + print(a == b) # True + print(a is b) # True + c = a.copy() + print(a == c) # True + print(a is c) # False + ``` + +5. **Looping Pitfalls**: Modifying a list while iterating over it can lead to unexpected behavior. Use slicing or create a new list instead. + +6. **Global vs Local Variables**: Variables declared inside a function are local unless explicitly declared global. + +7. **Floating Point Arithmetic**: Like many languages, Python's floating-point numbers can have rounding errors. + ```python + print(0.1 + 0.2 == 0.3) # False + ``` + +8. **GIL (Global Interpreter Lock)**: Python's GIL means that only one thread can execute Python bytecodes at a time. This can be a gotcha for CPU-bound multithreading applications. + +Understanding these Python-specific idioms and gotchas is crucial for leveraging Python's strengths while avoiding common pitfalls, ensuring your transition to Python is smooth and productive. \ No newline at end of file