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Sarah Tanveer

**Sets** are unordered data structures that do not contain duplicates.
In this shot, we will discuss how to determine if a set is a subset of another set.

If all the values of a set, A, are also contained in a larger set, B, then A is a subset of B.

`issubset()`

The built-in function ** issubset()** can be used to determine if a set is a subset of another set.

```
setA.issubset(setB)
```

The `issubset()`

function takes one argument: the larger set. Here, we are checking if `setA`

is a subset of `setB`

.

The function will return `True`

if `setA`

is a subset of `setB`

and `False`

if it is not.

setA = {1, 2, 3, 4, 5} setB = {1, 2, 3} setC = {1, 2, 3, 6, 7} print("setA: ", setA) print("setB: ", setB) print("setC: ", setC) print("Is setB a subset of setA?: ", setB.issubset(setA)) print("Is setA a subset of setB?: ", setA.issubset(setB)) print("Is setC a subset of setA?: ", setC.issubset(setA))

`intersection()`

The built-in ** intersection()** function returns a set that contains the elements that the two sets share.

```
set.intersection(set1)
```

If the set that `intersection`

returns is equal to the smaller set, the smaller set is a subset of the larger set.

setA = {1, 2, 3, 4, 5} setB = {1, 2, 3} setC = {1, 2, 3, 6, 7} print("setA: ", setA) print("setB: ", setB) print("setC: ", setC) print("Is setB a subset of setA?: ", setA.intersection(setB) == setB) print("Is setA a subset of setB?: ", setA.intersection(setB) == setA) print("Is setC a subset of setA?: ", setA.intersection(setC) == setC)

`for`

loopWe can use a simple `for`

loop to traverse through the potential subset, say, `setB`

.

If any element of `setB`

is not in the other set, `setA`

, then `setB`

is *not* a subset of `setA`

. Otherwise, `setB`

is a subset of `setA`

.

setA = {1, 2, 3, 4, 5} setB = {1, 2, 3} print("setA: ", setA) print("setB: ", setB) subSet = True for i in setB: if i not in setA: subSet = False if subSet == False: print("SetB is not a subset of SetA") else: print("SetB is a subset of SetA") for i in setA: if i not in setB: subSet = False if subSet == False: print("SetA is not a subset of SetB") else: print("SetA is a subset of SetB")

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