Follow Techotopia on Twitter

On-line Guides
All Guides
eBook Store
iOS / Android
Linux for Beginners
Office Productivity
Linux Installation
Linux Security
Linux Utilities
Linux Virtualization
Linux Kernel
System/Network Admin
Programming
Scripting Languages
Development Tools
Web Development
GUI Toolkits/Desktop
Databases
Mail Systems
openSolaris
Eclipse Documentation
Techotopia.com
Virtuatopia.com

How To Guides
Virtualization
General System Admin
Linux Security
Linux Filesystems
Web Servers
Graphics & Desktop
PC Hardware
Windows
Problem Solutions

  




 

 

Set Operations

There are a large number of set operations, including union (|), intersection (&), difference (-), symmetric difference (^). These are unusual operations, so we'll look at them in some detail. In addition to this operator notation, there are method functions which do the same things. We'll look at the method function versions below.

We'll use the following two sets to show these operators.

>>> 
fib=set( (1,1,2,3,5,8,13) )

>>> 
prime=set( (2,3,5,7,11,13) )

Union, |

The resulting set has elements from both source sets. An element is in the result if it is one set or the other.

>>> 
fib | prime

set([1, 2, 3, 5, 7, 8, 11, 13])

Figure 16.1. Set Union, S1|S2

Set Union, S1|S2
Intersection, &

The resulting set has elements that are common to both source sets. An element is in the result if it is in one set and the other.

>>> 
fib & prime

set([2, 3, 5, 13])

Figure 16.2. Set Intersection, S1&S2

Set Intersection, S1&S2
Difference, -

The resulting set has elements of the left-hand set with all elements from the right-hand set removed. An element will be in the result if it is in the left-hand set and not in the right-hand set.

>>> fib - prime
set([8, 1])
>>> prime - fib
set([11, 7])

Figure 16.3. Set Difference, S1-S2

Set Difference, S1-S2
Symmetric Difference, ^

The resulting set has elements which are unique to each set. An element will be in the result set if either it is in the left-hand set and not in the right-hand set or it is in the right-hand set and not in the left-hand set. Whew!

>>> 
fib ^ prime

set([8, 1, 11, 7])

Figure 16.4. Set Symmetric Difference, S2^S2

Set Symmetric Difference, S2^S2

 
 
  Published under the terms of the Open Publication License Design by Interspire