15-110 Lecture Topics:  Dictionaries

Week #8  Oct 11 – Oct 15

1. What is a dictionary?
1. It is a map from keys to values
2. Adding, removing, getting, and setting are all fast (eg, much faster than using a sorted list of tuples)
3. Keys are a set:  they are unique and unsorted
2. How to...
1. Create a dictionary
1. Create an empty dictionary
2. Create a dictionary from a list of tuples
2. Add a key/value
3. Delete a key
4. Get a value from a key
5. Modify a key/value
6. Get all keys
3. Usage
1. Can use mixed types for keys and values
2. Keys are case-sensitive
3. Don't use a dictionary like a list
4. Recommended Reading
1. http://docs.python.org/library/stdtypes.html#typesmapping
2. http://docs.python.org/tutorial/datastructures.html
3. http://diveintopython.org/getting_to_know_python/dictionaries.html