How to use is_len_call method in refurb

Best Python code snippet using refurb_python

subscripts.py

Source:subscripts.py

1import ast2from typing_extensions import final3from wemake_python_styleguide.logic import source4from wemake_python_styleguide.logic.tree import functions, operators, slices5from wemake_python_styleguide.violations import (6    best_practices,7    consistency,8    refactoring,9)10from wemake_python_styleguide.visitors import base11@final12class SubscriptVisitor(base.BaseNodeVisitor):13    """Checks subscripts used in the code."""14    def visit_Subscript(self, node: ast.Subscript) -> None:15        """16        Visits subscript.17        Raises:18            RedundantSubscriptViolation19        """20        self._check_redundant_subscript(node)21        self.generic_visit(node)22    def _check_redundant_subscript(self, node: ast.Subscript) -> None:23        if not isinstance(node.slice, ast.Slice):24            return25        lower_ok = (26            node.slice.lower is None or (27                not self._is_zero(node.slice.lower) and28                not self._is_none(node.slice.lower)29            )30        )31        upper_ok = (32            node.slice.upper is None or33            not self._is_none(node.slice.upper)34        )35        step_ok = (36            node.slice.step is None or (37                not self._is_one(node.slice.step) and38                not self._is_none(node.slice.step)39            )40        )41        if not (lower_ok and upper_ok and step_ok):42            self.add_violation(43                consistency.RedundantSubscriptViolation(44                    node, text=str(node),45                ),46            )47    def _is_none(self, component_value: ast.expr) -> bool:48        return (49            isinstance(component_value, ast.NameConstant) and50            component_value.value is None51        )52    def _is_zero(self, component_value: ast.expr) -> bool:53        return isinstance(component_value, ast.Num) and component_value.n == 054    def _is_one(self, component_value: ast.expr) -> bool:55        return isinstance(component_value, ast.Num) and component_value.n == 156@final57class ImplicitDictGetVisitor(base.BaseNodeVisitor):58    """Checks for correct ``.get`` usage in code."""59    def visit_If(self, node: ast.If) -> None:60        """61        Checks the compares.62        Raises:63            ImplicitDictGetViolation64        """65        self._check_implicit_get(node)66        self.generic_visit(node)67    def _check_implicit_get(self, node: ast.If) -> None:68        if not isinstance(node.test, ast.Compare):69            return70        if not isinstance(node.test.ops[0], ast.In):71            return72        checked_key = source.node_to_string(node.test.left)73        checked_collection = source.node_to_string(node.test.comparators[0])74        for sub in ast.walk(node):75            if not isinstance(sub, ast.Subscript):76                continue77            if slices.is_same_slice(checked_collection, checked_key, sub):78                self.add_violation(refactoring.ImplicitDictGetViolation(sub))79@final80class CorrectKeyVisitor(base.BaseNodeVisitor):81    """Checks for correct keys usage in your code."""82    def visit_Subscript(self, node: ast.Subscript) -> None:83        """84        Checks that key usage is correct, without any errors.85        Raises:86            FloatKeyViolation87            ImplicitNegativeIndexViolation88        """89        self._check_float_key(node)90        self._check_len_call(node)91        self.generic_visit(node)92    def _check_float_key(self, node: ast.Subscript) -> None:93        is_float_key = (94            isinstance(node.slice, ast.Index) and95            self._is_float_key(node.slice)96        )97        if is_float_key:98            self.add_violation(best_practices.FloatKeyViolation(node))99    def _check_len_call(self, node: ast.Subscript) -> None:100        is_len_call = (101            isinstance(node.slice, ast.Index) and102            isinstance(node.slice.value, ast.BinOp) and103            isinstance(node.slice.value.op, ast.Sub) and104            self._is_wrong_len(105                node.slice.value,106                source.node_to_string(node.value),107            )108        )109        if is_len_call:110            self.add_violation(111                refactoring.ImplicitNegativeIndexViolation(node),112            )113    def _is_wrong_len(self, node: ast.BinOp, element: str) -> bool:114        return (115            isinstance(node.left, ast.Call) and116            bool(functions.given_function_called(node.left, {'len'})) and117            source.node_to_string(node.left.args[0]) == element118        )119    def _is_float_key(self, node: ast.Index) -> bool:120        real_node = operators.unwrap_unary_node(node.value)121        return (122            isinstance(real_node, ast.Num) and123            isinstance(real_node.n, float)...

no_len_cmp.py

Source:no_len_cmp.py

...70            return True71        case DictExpr() | ListExpr() | StrExpr() | TupleExpr():72            return True73    return False74def is_len_call(node: CallExpr) -> bool:75    match node:76        case CallExpr(77            callee=NameExpr(fullname="builtins.len"),78            args=[arg],79        ) if is_builtin_container_like(arg):80            return True81    return False82IS_COMPARISON_TRUTHY: dict[tuple[str, int], bool] = {83    ("==", 0): False,84    ("<=", 0): False,85    (">", 0): True,86    ("!=", 0): True,87    (">=", 1): True,88}89class LenComparisonVisitor(TraverserVisitor):90    errors: list[Error]91    def __init__(self, errors: list[Error]) -> None:92        super().__init__()93        self.errors = errors94        for name, ty in METHOD_NODE_MAPPINGS.items():95            if ty in (ComparisonExpr, UnaryExpr, OpExpr, CallExpr):96                continue97            def inner(self: "LenComparisonVisitor", o: Node) -> None:98                return99            setattr(self, name, inner.__get__(self))100    def visit_comparison_expr(self, node: ComparisonExpr) -> None:101        match node:102            case ComparisonExpr(103                operators=[oper],104                operands=[CallExpr() as call, IntExpr(value=num)],105            ) if is_len_call(call):106                is_truthy = IS_COMPARISON_TRUTHY.get((oper, num))107                if is_truthy is None:108                    return109                expr = "x" if is_truthy else "not x"110                self.errors.append(111                    ErrorInfo(112                        node.line,113                        node.column,114                        f"Replace `len(x) {oper} {num}` with `{expr}`",115                    )116                )117    def visit_call_expr(self, node: CallExpr) -> None:118        if is_len_call(node):119            self.errors.append(120                ErrorInfo(node.line, node.column, "Replace `len(x)` with `x`")121            )122ConditionLikeNode = (123    IfStmt124    | MatchStmt125    | GeneratorExpr126    | DictionaryComprehension127    | ConditionalExpr128    | WhileStmt129    | AssertStmt130)131def check(node: ConditionLikeNode, errors: list[Error]) -> None:132    check_condition_like(LenComparisonVisitor(errors), node)...

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