difference
set.difference
Returns a NEW set with elements from s that are NOT in any of the arguments. Method form takes iterables; - requires sets.
s.difference(*others) | s - otherParameters
| Parameter | Purpose |
|---|---|
| *others | Iterables or sets whose elements are subtracted from s |
| returns | A new set — s is unchanged |
Examples
>>> {1, 2, 3, 4} - {2, 4}
{1, 3}Subtracts elements found in the right-hand set.
>>> {1, 2, 3}.difference([2], [3])
{1}Multiple iterables are all subtracted.
>>> {1, 2} - {3, 4}
{1, 2}No overlap — result equals the left set.
>>> a = {1, 2}; b = {2, 3}
>>> a - b == b - a
FalseDifference is NOT commutative; a-b keeps only a's exclusives.
Gotcha
Difference is asymmetric: a - b keeps elements only in a. For elements in either but not both, use symmetric_difference (^).
Related methods
set.difference_update
Removes from s in place every element found in any of the given iterables. Method form accepts iterables; -= requires sets.
set.symmetric_difference
Returns a NEW set with elements in EITHER s or other but not both. Method form takes exactly one iterable; ^ requires a set.
set.intersection
Returns a NEW set containing only elements found in s AND in every argument. Method form accepts any iterables; & requires sets.
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