- Subtraction / set difference
Last updated: 2026-09-22
- Subtraction / set difference
- subtracts numbers and computes set difference.
| Category | Operators |
|---|---|
| Kind | Operator |
| Python Version | all |
📝 Syntax
a - b▶ Example
Edit the code, press Run, and see the result in the output panel:
Output：
7
{1, 3}💡 Related Cases
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❓ FAQ
QCan a list use `-` directly?
ANo. `[1, 2] - [2]` raises `TypeError`. To compute a difference, first convert to sets: `set([1, 2]) - set([2])`, but note that sets are unordered, so the order of the result is not guaranteed.
QWhat is the single-minus `-x` operation?
AIt is the unary negation: when `x = 5`, `-x` gives `-5`. It is a different operator from the binary subtraction `a - b`.
QDo float subtractions have precision issues?
AYes. For example, `0.3 - 0.1` yields `0.19999999999999998`, a limitation of binary floating-point representation. For exact decimal computation, use `decimal.Decimal`.
