1. Python Data Structures
CS 265
Seth Simpson

2. Lists Creating Lists List methods exampleList = [1,3,5,7,9]
Append(element) – appends element to end
Extend(list) – extends the list with another list
Insert(position, element) – insert element at the given position
Remove(element) – removes the first occurrence of the element

3. Lists (Cont) More List methods
Pop(index) – Remove and return the element at index (last element by default)
Index(element) – returns index of the first occurrence of element
Count(element) – returns the number of times element appears in the list
Sort() – sorts the list
Reverse() – reverses the list

4. Example of List Methods

5. Lists as Stacks Last in – First out
List pop function enables us to treat lists as stacks.

6. Lists as Queues First in – first out
Popping end elements of a list is fast because the elements don’t need to be rearranged
Popping from the front of a list is slow because the list needs to be rearranged

7. List Filtering Filter(function name, list)
Returns a sequence of items for which function(item) is true.
Example:

8. List Mapping Map(function name, list)
Calls the function for each value in the list and outputs the results as list
Example:

9. List Reducing Reduce(function name, list)
Returns a single value by computing the function value on the first two elements, then the result of that with the next element and so on.

10. Sets
Unordered collection with no duplicates

11. Sets (Cont)

12. Dictionaries
Unsorted set of Key : Value pairs

13. Dictionaries (Cont)
Can also call the dict() constructor to create a dictionary.
Printing out Dictionaries