This document contains some anti-patterns that have either been discussed during code-reviews or noticed by some one when refactoring any of GN's code-base. Use these "ideas" as a reference, and apply reasonable judgement depending on what you are working on.
Consider:
from typing import List
_l = ['a', 'b', 'c']
def add_pvalue(l: List, val: str) -> List:
l.append(val)
return l
print(f"{_l=}\n")
print(f"{add_pvalue(_l, 'd')=}\n")
print(f"{_l=}")
which outputs (note that _l in the global scope has changed):
_l=['a', 'b', 'c'] add_pvalue(_l, 'd')=['a', 'b', 'c', 'd'] _l=['a', 'b', 'c', 'd']
A better fix would be:
from typing import List
_l = ['a', 'b', 'c']
def add_pvalue(l: List, val: str) -> List:
l = l.copy()
l.append(val)
return l
print(f"{_l=}\n")
print(f"{add_pvalue(_l, 'd')=}\n")
print(f"{_l=}")
which now does the right thing:
_l=['a', 'b', 'c'] add_pvalue(_l, 'd')=['a', 'b', 'c', 'd'] _l=['a', 'b', 'c']
Best, use immutable types:
from typing import Tuple
_l = ['a', 'b', 'c']
def add_pvalue(l: Tuple, val: str) -> Tuple:
return l + (val,)
print(f"{_l=}\n")
print(f"{add_pvalue(tuple(_l), 'p')=}\n")
print(f"{_l=}")
which outputs:
_l=['a', 'b', 'c']
add_pvalue(tuple(_l), 'p')=('a', 'b', 'c', 'p')
_l=['a', 'b', 'c']