tl;dr: As the reference manual states: A block is a piece of Python program text that is executed as a unit. The following are blocks: a module, a function body, and a class definition. Each command typed interactively is a block. This is why, in the case of a function, you have a single code … Read more
Sure! The code’s here, starting with function islt and proceeding for QUITE a while;-). As Chris’s comment suggests, it’s C code. You’ll also want to read this text file for a textual explanation, results, etc etc. If you prefer reading Java code than C code, you could look at Joshua Bloch’s implementation of timsort in … Read more
You should watch this video (although it is CPython1 specific and about dictionaries — but I assume it applies to sets as well). Basically, python hashes the elements and takes the last N bits (where N is determined by the size of the set) and uses those bits as array indices to place the object … Read more
How does asyncio work? Before answering this question we need to understand a few base terms, skip these if you already know any of them. Generators Generators are objects that allow us to suspend the execution of a python function. User curated generators are implement using the keyword yield. By creating a normal function containing … Read more
Python separates the right-hand side expression from the left-hand side assignment. First the right-hand side is evaluated, and the result is stored on the stack, and then the left-hand side names are assigned using opcodes that take values from the stack again. For tuple assignments with 2 or 3 items, Python just uses the stack … Read more
Firstly, you can del other things besides local variables del list_item[4] del dictionary[“alpha”] Both of which should be clearly useful. Secondly, using del on a local variable makes the intent clearer. Compare: del foo to foo = None I know in the case of del foo that the intent is to remove the variable from … Read more
When you call id({}), Python creates a dict and passes it to the id function. The id function takes its id (its memory location), and throws away the dict. The dict is destroyed. When you do it twice in quick succession (without any other dicts being created in the mean time), the dict Python creates … Read more
The C code is pretty simple, actually. Expanding one macro and pruning some irrelevant comments, the basic structure is in listobject.h, which defines a list as: typedef struct { PyObject_HEAD Py_ssize_t ob_size; /* Vector of pointers to list elements. list[0] is ob_item[0], etc. */ PyObject **ob_item; /* ob_item contains space for ‘allocated’ elements. The number … Read more
CPython does not promise to intern all strings by default, but in practice, a lot of places in the Python codebase do reuse already-created string objects. A lot of Python internals use (the C-equivalent of) the sys.intern() function call to explicitly intern Python strings, but unless you hit one of those special cases, two identical … Read more
This is implementation-specific, but your interpreter is probably interning compile-time constants but not the results of run-time expressions. In what follows CPython 3.9.0+ is used. In the second example, the expression “strin”+”g” is evaluated at compile time, and is replaced with “string”. This makes the first two examples behave the same. If we examine the … Read more