Python Set union() method returns a new set with unique elements from all the sets. The result will contain only one item’s appearance if the element is present in more than one set.

For example, if **A = {2,5,7} **and** B = {1,2,5,8} **are two sets, then the Union of** **these two sets will be **AUB={1,2,5,7,8}, **though 2 and 5 are common in both the sets, but in result set it will be taken only once.

**Visual Representation**

**Syntax**

`set1.union(set2, set3, set4...)`

**Parameters**

set1 |
It is required. The iterable to unify with |

set2 |
It is optional. The other is iterable to unify with. You can compare as many iterables as you like. Separate each iterable with a comma. |

**Return Value**

This method returns a new set with elements from the set and all other sets (passed as an argument). If the argument is not passed to union(), it returns a shallow copy of the set.

**Example 1: How to Use Set union() Method**

```
set1 = {2, 4, 6, 8, 10}
# Multiple of 3 between 1 to 10
set2 = {3, 6, 9}
# All prime numbers between 1 to 10
set3 = {2, 3, 5, 7}
# priting both the sets
print("Set1 is: ", set1)
print("Set2 is : ", set2)
print("Set3 is: ", set3)
# Now we will find Union of these sets
print("Union of set1 and set2 is: ", set1.union(set2))
print("Union of set1 and set2,set3 is: ", set1.union(set2, set3))
```

**Output**

```
Set1 is: {2, 4, 6, 8, 10}
Set2 is : {9, 3, 6}
Set3 is: {2, 3, 5, 7}
Union of set1 and set2 is: {2, 3, 4, 6, 8, 9, 10}
Union of set1 and set2,set3 is: {2, 3, 4, 5, 6, 7, 8, 9, 10}
```

**Example 2: Set Union Using the | Operator**

```
set1 = {2, 4, 6, 8, 10}
# Multiple of 3 between 1 to 10
set2 = {3, 6, 9}
# All prime numbers between 1 to 10
set3 = {2, 3, 5, 7}
# priting both the sets
print("Set1 is: ", set1)
print("Set2 is : ", set2)
print("Set3 is: ", set3)
# Now we will find Union of these sets
print("Union of set1 and set2 is: ", set1 | set2)
print("Union of set1 and set2,set3 is: ", set1 | set2 | set3)
```

**Output**

```
Set1 is: {2, 4, 6, 8, 10}
Set2 is : {9, 3, 6}
Set3 is: {2, 3, 5, 7}
Union of set1 and set2 is: {2, 3, 4, 6, 8, 9, 10}
Union of set1 and set2,set3 is: {2, 3, 4, 5, 6, 7, 8, 9, 10}
```

Ankit Lathiya is a Master of Computer Application by education and Android and Laravel Developer by profession and one of the authors of this blog. He is also expert in JavaScript and Python development.