More on Dictionaries

1. More on Dictionaries CSE 1310 – Introduction to Computers and Programming Christopher Conly University of Texas at Arlington

2. Legal Keys • No duplicate keys • Cannot have multiple entries for a key

3. Legal Keys • No duplicate keys • Cannot have multiple entries for a key • Keys must be immutable types

4. Legal Keys • No duplicate keys • Cannot have multiple entries for a key • Keys must be immutable types • Strings • Integers • Tuples • Mix and match is okay

5. Nesting Dictionaries • A dictionary with dictionaries as values my_dict = {123: {'name': 'John', 'age': 50}, 456: {'name': 'Mary', 'age': 30}} • Outer dictionary brackets?

6. Nesting Dictionaries • A dictionary with dictionaries as values my_dict = {123: {'name': 'John', 'age': 50}, 456: {'name': 'Mary', 'age': 30}} • Outer dictionary brackets

7. Nesting Dictionaries • A dictionary with dictionaries as values my_dict = {123: {'name': 'John', 'age': 50}, 456: {'name': 'Mary', 'age': 30}} • Outer dictionary keys?

8. Nesting Dictionaries • A dictionary with dictionaries as values my_dict = {123: {'name': 'John', 'age': 50}, 456: {'name': 'Mary', 'age': 30}} • Outer dictionary keys

9. Nesting Dictionaries • A dictionary with dictionaries as values my_dict = {123: {'name': 'John', 'age': 50}, 456: {'name': 'Mary', 'age': 30}} • Outer dictionary values?

10. Nesting Dictionaries • A dictionary with dictionaries as values my_dict = {123: {'name': 'John', 'age': 50}, 456: {'name': 'Mary', 'age': 30}} • Outer dictionary values

11. Nesting Dictionaries • A dictionary with dictionaries as values my_dict = {123: {'name': 'John', 'age': 50}, 456: {'name': 'Mary', 'age': 30}} • Inner dictionary brackets?

12. Nesting Dictionaries • A dictionary with dictionaries as values my_dict = {123: {'name': 'John', 'age': 50}, 456: {'name': 'Mary', 'age': 30}} • Inner dictionary brackets

13. Nesting Dictionaries • A dictionary with dictionaries as values my_dict = {123: {'name': 'John', 'age': 50}, 456: {'name': 'Mary', 'age': 30}} • Inner dictionary keys?

14. Nesting Dictionaries • A dictionary with dictionaries as values my_dict = {123: {'name': 'John', 'age': 50}, 456: {'name': 'Mary', 'age': 30}} • Inner dictionary keys

15. Nesting Dictionaries • A dictionary with dictionaries as values my_dict = {123: {'name': 'John', 'age': 50}, 456: {'name': 'Mary', 'age': 30}} • Inner dictionary values?

16. Nesting Dictionaries • A dictionary with dictionaries as values my_dict = {123: {'name': 'John', 'age': 50}, 456: {'name': 'Mary', 'age': 30}} • Inner dictionary values

17. Accessing Nested Dictionaries my_dict = {123: {'name': 'John', 'age': 50}, 456: {'name': 'Mary', 'age': 30}} How do you access 'John'?

18. Accessing Nested Dictionaries my_dict = {123: {'name': 'John', 'age': 50}, 456: {'name': 'Mary', 'age': 30}} How do you access 'John'? my_dict[123]['name']

19. Accessing Nested Dictionaries my_dict = {123: {'name': 'John', 'age': 50}, 456: {'name': 'Mary', 'age': 30}} How do you access 'John'? my_dict[123]['name']

20. Accessing Nested Dictionaries my_dict = {123: {'name': 'John', 'age': 50}, 456: {'name': 'Mary', 'age': 30}} How do you access 'John'? my_dict[123]['name']

21. Looping and Dictionaries my_dict = {123: {'name': 'John', 'age': 50}, 456: {'name': 'Mary', 'age': 30}} for item in my_dict: ... What is item?

22. Looping and Dictionaries my_dict = {123: {'name': 'John', 'age': 50}, 456: {'name': 'Mary', 'age': 30}} for item in my_dict: ... What is item? A key. How do we access the name value?

23. Looping and Dictionaries my_dict = {123: {'name': 'John', 'age': 50}, 456: {'name': 'Mary', 'age': 30}} for item in my_dict: name = my_dict[item]['name'] How do access the name value?

24. Looping and Dictionaries my_dict = {123: {'name': 'John', 'age': 50}, 456: {'name': 'Mary', 'age': 30}} for item in my_dict: name = my_dict[item]['name'] How do access the name value?

25. Looping and Dictionaries my_dict = {123: {'name': 'John', 'age': 50}, 456: {'name': 'Mary', 'age': 30}} for item in my_dict: name = my_dict[item]['name'] How do access the name value?

26. Looping and Dictionaries my_dict = {123: {'name': 'John', 'age': 50}, 456: {'name': 'Mary', 'age': 30}} for item in my_dict: name = my_dict[item]['name'] How do access the name value?

27. Looping and Dictionaries my_dict = {123: {'name': 'John', 'age': 50}, 456: {'name': 'Mary', 'age': 30}} for key1 in my_dict: ... What about looping through ‘name’ and ‘age’?

28. Looping and Dictionaries my_dict = {123: {'name': 'John', 'age': 50}, 456: {'name': 'Mary', 'age': 30}} for key1 in my_dict: for key2 in my_dict[key1]: print my_dict[key1][key2] What about looping through ‘name’ and ‘age’?

29. Looping and Dictionaries my_dict = {123: {'name': 'John', 'age': 50}, 456: {'name': 'Mary', 'age': 30}} for key1 in my_dict: for key2 in my_dict[key1]: print my_dict[key1][key2] What about looping through ‘name’ and ‘age’?

30. Looping and Dictionaries my_dict = {123: {'name': 'John', 'age': 50}, 456: {'name': 'Mary', 'age': 30}} for key1 in my_dict: for key2 in my_dict[key1]: print my_dict[key1][key2] What about looping through ‘name’ and ‘age’?

31. Looping and Dictionaries my_dict = {123: {'name': 'John', 'age': 50}, 456: {'name': 'Mary', 'age': 30}} for key1 in my_dict: for key2 in my_dict[key1]: print my_dict[key1][key2] What about looping through ‘name’ and ‘age’?

32. Looping and Dictionaries my_dict = {123: {'name': 'John', 'age': 50}, 456: {'name': 'Mary', 'age': 30}} for key1 in my_dict: for key2 in my_dict[key1]: print my_dict[key1][key2] What about looping through ‘name’ and ‘age’?