KnowCardPython · Math, random & Decimal
Why is if x == math.nan: always wrong, no matter what x is?
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More in Math, random & Decimal
What does this print?
```
print(round(0.5), round(2.5))
print(round(1.5), round(3.5))
```
You need to round prices half-up (2.5 -> 3, never 2). Why won't built-in round() do it, and what does?
What is the difference in result and return type between math.floor(-2.5), math.trunc(-2.5), and math.ceil(-2.5)?
You compare two values near zero with math.isclose(a, 0.0). Why might it return False even when a is tiny, and how do you fix it?
What does this print?
```
import math
nan = math.nan
print(nan == nan)
print(math.isnan(nan))
```
What does this print?
```
from decimal import Decimal
print(Decimal("0.1") + Decimal("0.2"))
```
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