Merge pull request #8746 from iam-sakshi/python1

Python1

Python/Set_Methods/set.md

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+# Sets in Python 
+
+- Unordered collection of distinct elements
+- Can contain elements of different types.
+- Sets are not hashable
+- Can only contain hashable items.
+- Enclosed inside curly braces and separated by symbol comma(,)
+
+## Declare Empty set
+
+``` python
+ set1 = set ( )
+```
+set1(variable name) is initialised to empty set using set function.
+
+## Initialising a set
+
+### Initialising a set with similar Data 
+
+``` python
+s1 = {"a","b","c","a"}
+print (s1)
+
+# Output : {"a","b","c"} it can be in any order , but only unique value will be stored
+```
+### Initialising a set with mixed Data 
+``` python
+s2 = {1,2.2,"abc",4}
+```
+## Finding Length of the set
+
+``` python
+s1 = ["a","b",22,9.0]
+print ( len ( s1 ) )
+
+# Output : 4
+```
+## Union of two sets
+
+It will return the union of two sets as a new set 
+
+``` python
+s1={1,4,5,6,2,3,9}
+s2={8,7,4,10,9,12}
+s = s1.union(s2)
+print (s)
+
+# Output : {1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 12}
+
+```
+or
+
+``` python
+s1={1,4,5,6,2,3,9}
+s2={8,7,4,10,9,12}
+s = s1 | s2
+print (s)
+
+# Output : {1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 12}
+
+```
+## Intersection of two sets
+
+It will return the intersection of two sets as a new set 
+
+``` python
+s1={1,4,5,6,2,3,9}
+s2={8,7,4,10,9,12}
+s = s1.intersection(s2)
+print (s)
+
+# Output : {9,4}
+
+```
+or
+
+``` python
+s1={1,4,5,6,2,3,9}
+s2={8,7,4,10,9,12}
+s = s1 & s2
+print (s)
+
+# Output : {9,4}
+
+```
+## Difference of two sets
+
+It will return the difference of two sets as a new set 
+
+``` python
+s1={1,4,5,6,2,3,9}
+s2={8,7,4,10,9,12}
+s = s1.difference(s2)
+print (s)
+
+# Output : {1, 2, 3, 5, 6}
+
+```
+or
+
+``` python
+s1={1,4,5,6,2,3,9}
+s2={8,7,4,10,9,12}
+s = s1 - s2
+print (s)
+
+# Output : {1, 2, 3, 5, 6}
+
+```
+## Symmetric Difference of two sets
+
+It will return the symmetric difference of two sets as a new set 
+
+``` python
+s1={1,4,5,6,2,3,9}
+s2={8,7,4,10,9,12}
+s = s1.symmetric_difference(s2)
+print (s)
+
+# Output : {1, 2, 3, 5, 6, 7, 8, 10, 12}
+
+```
+or
+
+``` python
+s1={1,4,5,6,2,3,9}
+s2={8,7,4,10,9,12}
+s = s1 ^ s2
+print (s)
+
+# Output : {1, 2, 3, 5, 6, 7, 8, 10, 12}
+
+```
+
+## Membership Operator in List
+
+- in  : returns true,  if the value present in set.
+- not in : returns true , if the value is not present in the set. 
+
+``` python
+s1={1,4,5,6,2,3,9}
+s2={8,7,4,10,9,12}
+if 5 in s1:
+    print ("found")
+else:
+    print("not found")    
+
+# Output : found
+
+```
+
+## Add element in a set
+
+we cannot access using index as set is unordered.
+
+``` python
+s1={1,4,5,6,2,3,9}
+s1.add(10)  
+print(s1)
+# Output : {1,4,5,6,2,10,3,9}
+```
+the element will be added but since the set are unordered so we cannot predict its position.
+
+## Remove element from set
+to remove particular value from the set .
+``` python
+s1={1,4,5,6,2,3,9}
+s1.remove(6)  
+print(s1)
+
+# Output : {1,4,5,2,9,3}
+```
+If the element is not present it will show an error.
+
+## Discard element from set
+To discard particular value from the set.
+``` python
+s1={1,4,5,6,2,3,9}
+s1.remove(9)  
+print(s1)
+
+# Output : {1,4,5,2,6,3}
+```
+if the element is not present it will not show any error.
+
+## Clear the Set
+To remove all the elements from the set.
+
+``` python
+s1={1,4,5,6,2,3,9}
+s1.clear()  
+print(s1)
+
+# Output : set()
+```