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from dataclasses import dataclass
from mypy.nodes import CallExpr, FloatExpr, IntExpr, RefExpr
from refurb.error import Error
@dataclass
class ErrorInfo(Error):
"""
Use the shorthand `log2` and `log10` functions instead of passing 2 or 10
as the second argument to the `log` function. If `math.e` is used as the
second argument, just use `math.log(x)` instead, since `e` is the default.
Bad:
```
power = math.log(x, 10)
```
Good:
```
power = math.log10(x)
```
"""
name = "simplify-math-log"
code = 163
categories = ("math", "readability")
def check(node: CallExpr, errors: list[Error]) -> None:
match node:
case CallExpr(
callee=RefExpr(fullname="math.log"),
args=[_, arg],
):
match arg:
case IntExpr(value=2 | 10) | FloatExpr(value=2.0 | 10.0):
base = str(arg.value)
new = f"math.log{int(arg.value)}(x)"
case RefExpr(fullname="math.e"):
base = "math.e"
new = "math.log(x)"
case _:
return
errors.append(ErrorInfo.from_node(node, f"Replace `math.log(x, {base})` with `{new}`"))
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