Sets in Python
Sets :​
A set in Python is an unordered collection of unique items. It is a data type that acts like a mathematical set. It is defined by enclosing the items within curly braces {} and each item seperated by (,).
Properties of Sets​
Unorderd :​
Unordered means that the items in a set are not stored in any particular order.
Example :
mycolors = {'sky','pink','yellow','green'}
print(mycolors)
Output :
{'yellow', 'pink', 'sky', 'green'}
Example Explanation :
In the above example, In the 1st line we can create one variable and the name of that variable is mycolors. In this variable, we store the set of items {'sky','pink','yellow','green'} and In 2nd line we can print the value of that variable.
Unindexed :​
Unindexed means that the items in a set you can not access that items by position or index.
Example :
mycolor = {'sky','pink','yellow','green','green'}
print(mycolor)
Output :
{'yellow', 'pink', 'sky', 'green'}
Example Explanation :
In the above example, In the 1st line we can create one variable and the name of that variable is mycolors. In this variable, we store the set of items {'sky','pink','yellow','green','green'} and In 2nd line we can print the value of that variable.
Unique values :​
Unique values means that the items in a set cannot contain duplicate items. If you try to add a duplicate items to a set, it will be ignored.
Example :
mycolor = {'orange','sky','pink','sky','green','sky','sky'}
print(mycolor)
Output :
{'pink', 'orange', 'sky', 'green'}
Example Explanation :
In the above example, In the 1st line we can create one variable and the name of that variable is mycolors. In this variable, we store the set of items {'orange','sky','pink','sky','green','sky','sky'} and In 2nd line we can print the value of that variable.
Adding values to Sets​
- add() method : The add() method is used to adds an element to the set. But position is not decide because set are unorderd.
Example :
mycolors = {'orange','sky','pink','sky','green'}
print("Before adding Value : ",mycolors)
mycolors.add('white')
print("After adding Value : ",mycolors)
Output :
Before adding Value : {'pink', 'orange', 'sky', 'green'}
After adding Value : {'orange', 'sky', 'green', 'white', 'pink'}
Example Explanation :
In the above example, In the 1st line we can create one variable and the name of that variable is mycolors. In this variable, we store the set of items {'orange','sky','pink','sky','green'}. In 2nd line we can print the value of that variable with adding proper sentence. In 3rd line we use add() method for adding new color in your set which is white. In 4th line we can print the value of that variable with adding proper sentence.
Remove Elements to Sets​
Hard Removal => In this case we used remove() method and it is used to remove element from the set.
Example :
mycolors = {'orange','sky','pink','sky','green'}
print("Brfore remove : ",mycolors)
mycolors.remove('blue')
print("After remove :",mycolors)
Output :
KeyError: 'blue'
Example Explanation :
In the above example, In the 1st line we can create one variable and the name of that variable is mycolors. In this variable, we store the set of items {'orange','sky','pink','sky','green'}. In 2nd line we can print the value of that original set. In 3rd line we use remove() method for removing color from your set which is blue. In 4th line we can print the value of the value of variable after removing the item in the set. In this case, in the output, we show an error because the blue color is not present in the set.
When using the remove() method in Python, you need to provide the item you want to remove from the set, and if the item is not present in the set, it will shows an error message.
Soft Removal => In this case we used discard() method.
Example :
mycolors = {'orange','sky','pink','sky','green'}
print("Brfore discard : ",mycolors)
mycolors.discard('blue')
print("After discard :",mycolors)
Output
Brfore discard : {'green', 'sky', 'pink', 'orange'}
After discard : {'green', 'sky', 'pink', 'orange'}
Example Explanation :
In the above example, In the 1st line we can create one variable and the name of that variable is mycolors. In this variable, we store the set of items {'orange','sky','pink','sky','green'}. In 2nd line we can print the value of that original set. In 3rd line we use discard() method for removing color from your set which is blue. In 4th line we can print the value of the value of variable after removing the item in the set. In this case, in the output, we show an original set because the blue color is not present in the set and this case the discard() method simply ignored it.
When using the discard() method in Python, you need to provide the item you want to remove from the set, and if the item is not present in the set, it will simply ignored it and print your original set.
Union of Sets​
The union() method returns a set that contains all items from the original set, and all items from the specified set.
Example :
colorList1 = {'sky','blue','white','black'}
colorList2 = {'yellow','green','red','sky'}
allElements = colorList1.union(colorList2)
print(allElements)
Output :
{'black', 'sky', 'red', 'blue', 'yellow', 'green', 'white'}
Example Explanation :
In the above example, In the 1st line we can create one variable and the name of that variable is colorList1.
In this variable, we store the set of items {'sky','blue','white','black'}. In the 2nd line we can create second variable and the name of that variable is colorList2. In this variable, we store the set of items {'yellow','green','red','sky'}. In th 3rd line we can create 3rd variable and the name of that variable is allElements. In this variable, we use the union() method for combining two sets in a single set. In 4th line we can print the value of that variable and the name of that variable is allElements.
Intersection of Sets​
The intersection() method returns a set that contains the similarity between two or more sets.
Example :
colorList1 = {'sky','blue','white','black'}
colorList2 = {'yellow','green','red','sky','black'}
sameElements = colorList1.intersection(colorList2)
print(sameElements)
Output
{'sky', 'black'}
Example Explanation :
In the above example, In the 1st line we can create one variable and the name of that variable is colorList1.
In this variable, we store the set of items {'sky','blue','white','black'}. In the 2nd line we can create second variable and the name of that variable is colorList2. In this variable, we store the set of items {'yellow','green','red','sky','black'}. In th 3rd line we can create third variable and the name of that variable is sameElements. In this variable, we use the intersection() method and it is used to find same items and store that items in single set. In 4th line we can print the value of that variable and the name of that variable is sameElements.
Symmetric Differnce​
The symmetric_difference() method returns a set that ignore the similarity between two or more sets.
Example :
colorList1 = {'sky','blue','white','black'}
colorList2 = {'yellow','green','red','sky','black'}
diffElements = colorList1.symmetric_difference(colorList2)
print(diffElements)
Output
{'blue', 'yellow', 'green', 'white', 'red'}
Example Explanation :
In the above example, In the 1st line we can create one variable and the name of that variable is colorList1.
In this variable, we store the set of items {'sky','blue','white','black'}. In the 2nd line we can create second variable and the name of that variable is colorList2. In this variable, we store the set of items {'yellow','green','red','sky','black'}. In th 3rd line we can create third variable and the name of that variable is diffElements. In this variable, we use the symmetric_difference() method and it is used to find different items and store that items in single set. In 4th line we can print the value of that variable and the name of that variable is diffElements.