1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
|
from dataclasses import dataclass
from mypy.nodes import CallExpr, IndexExpr, IntExpr, NameExpr, SliceExpr
from refurb.error import Error
@dataclass
class ErrorInfo(Error):
"""
The `bin()`, `oct()`, and `hex()` functions return the string
representation of a number but with a prefix attached. If you don't want
the prefix, you might be tempted to just slice it off, but using an
f-string will give you more flexibility and let you work with negative
numbers:
Bad:
```
print(bin(1337)[2:])
```
Good:
```
print(f"{1337:b}")
```
"""
name = "use-fstring-number-format"
code = 116
categories = ("builtin", "fstring")
FUNC_CONVERSIONS = {
"builtins.bin": "b",
"builtins.oct": "o",
"builtins.hex": "x",
}
def check(node: IndexExpr, errors: list[Error]) -> None:
match node:
case IndexExpr(
base=CallExpr(callee=NameExpr() as name_node),
index=SliceExpr(begin_index=IntExpr(value=2), end_index=None),
) if name_node.fullname in FUNC_CONVERSIONS:
format = FUNC_CONVERSIONS[name_node.fullname or ""]
fstring = f'f"{{num:{format}}}"'
errors.append(
ErrorInfo.from_node(
node,
f"Replace `{name_node.name}(num)[2:]` with `{fstring}`",
)
)
|
