Python Set difference_update() Method
Example
Remove the items that exist in both sets:
x =
{"apple", "banana", "cherry"}
y = {"google",
"microsoft", "apple"}
x.difference_update(y)
print(x)
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Definition and Usage
The difference_update() method removes the
items that exist in both sets.
The difference_update() method is different
from the difference() method, because the difference()
method returns a new set, without the unwanted items, and the
difference_update() method removes the
unwanted items from the original set.
As a shortcut, you can use the -= operator instead, see example below.
Syntax
set.difference_update(set1, set2 ... etc.)
Parameter Values
| Parameter | Description |
|---|---|
| set1 | Required. The set(s) to check for differences in. |
| set2 | Optional. The other set to search for equal items in. You can compare as many sets you like. Separate the sets with a comma. See examples below. |
Shorter Syntax
set -= set1 | set2 ... etc.
Parameter Values
| Parameter | Description |
|---|---|
| set1 | Required. The set(s) to check for differences in. |
| set2 | Optional. The other set to search for equal items in. You can compare as many sets you like. Separate the sets with |
(a pipe operator).See examples below. |
More Examples
Example
Use -= as a shortcut instead of difference_update():
a =
{"apple", "banana", "cherry"}
b = {"google",
"microsoft", "apple"}
a -= b
print(a)
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Example
Join more than two sets:
a =
{"apple", "banana", "cherry"}
b = {"google",
"microsoft", "apple"}
c = {"cherry",
"micra", "bluebird"}
a.difference_update(b, c)
print(a)
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Example
Join more than two sets with the -= operator:
a =
{"apple", "banana", "cherry"}
b = {"google",
"microsoft", "apple"}
c = {"cherry",
"micra", "bluebird"}
a -= b | c
print(myset)
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Related Pages
Tutorial: Python Sets
Tutorial: Join Python Sets
Method: difference()
