Basic Python Programming Code Snippets:

Tuple Data Structure

Create a Tuple

Much like the set data structure, you can create a tuple in two ways. You can:

• assign your variable to a specified group of elements enclosing them in parenthesis.
• variable = (x, y, z)

or;


• assign your variable to a list data structure and use the tuple() constructor which takes the list as a parameter.
• variable = tuple([x, y, z])
• variable = tuple(myList) # myList is a list of U.S. States. See the article on List Data Structure

The example below uses the first option of manually specifying the elements of the set and enclosing them in parenthesis.

myTuple = ( 'Florida',
'Illinois',
'Pennsylvania',
'Ohio',
'Georgia',
'North Carolina',
'Michigan',
'Virginia',
'Washington',
'Massachusetts',
'Arizona',
'Indiana',
'Tennessee',
'Missouri',
'Maryland',
'Wisconsin',
'Minnesota',
'Colorado',
 'Alabama',
 'South Carolina',
 'Louisiana',
'Kentucky',
'Oregon',
 'Oklahoma',
 'Connecticut',
 'Iowa',
 'Arkansas',
'Mississippi',
 'Utah',
 'Kansas',
'Nevada',
'New Mexico',
'Nebraska',
'West Virginia',
 'Idaho',
 'Hawaii',
 'Maine',
 'New Hampshire',
'Rhode Island',
 'Montana',
'Delaware',
 'South Dakota',
 'North Dakota',
'Alaska',
'Vermont',
'Wyoming',
'New Jersey',
'New York',
'California',
'Texas')

Understanding Indexing to Access Tuple Elements

Like lists, tuples are accessed by their index. For tuples (and lists), each element is assigned a number indicating its position. We call this position an "index." The first item of the tuple is indexed as zero, the second is indexed as one, the third is indexed as two, and so on. In our example, Florida is indexed as 0, the first item of the tuple. Texas is indexed as 49, the last item of the tuple. In order to print Texas (or the last item in the tuple), the following syntax is used:

print(myTuple[49])

If, however, there was an attempt to call a function on an item indexed at position 50, an error would be returned as there are only 50 items in the tuple and the last item is indexed at 49.

print(myTuple[50] #should return an error

Immutability

Because tuples are immutable (they cannot be changed once created), methods for adding, updating, and deleting elements are all unavailable.

Conclusion

Tuples are an important data structure. They provide a lightweight and efficient way to store collections of objects. While they are very similar to lists, their immutability is a distinguishing factor. Immutability can be a useful property. If you need to store a collection of values with the assurance that they will not be changed, tuples are a viable programming option. Needless to say, tuples are an important structure and understanding them will likely be beneficial to you at some point in your Python Developer career.

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