l A simple dictionary
| 1 2 | alien_0 = {'color': 'green','point': 5} print(alien_0['color'])#使用大括号 |
The window will show green.
l Using dictionary
n Add key-value pair
For example,
| 1 2 3 4 5 6 | alien_0 = {'color': 'green','point': 5} print(alien_0['color']) alien_0['x_position'] = 0 alien_0['y_position'] = 25 print(alien_0) |
The window will show
| 1 | {'color': 'green', 'point': 5, 'x_position': 0, 'y_position': 25} |
Modify the key-value pair
| 1 | alien_0['color'] = 'yellow' |
Delete the key-value pair
Use del is OK.
For example,
| 1 | del alien_0['points'] |
Dictionary will not include points.
Dictionary just like struct in C language.
The dictionary which consists of many objects:
For example,
| 1 2 3 4 5 6 7 8 9 10 | favorite_languages = { 'David': 'python', 'Jane' : 'java', 'John' : 'C', 'Sarah' : 'ruby', 'Michel' : 'swift' } print("David's favorite languages is " + favorite_languages['David'].title() + ".") |
It will show,
| 1 | David's favorite languages is Python. |
Remember the format!
l Ergodic dictionary
n Ergodic all key-value pairs
Method: items(): items()方法用于返回字典dict的(key，value)元组对的列表
Ergodic all keys
Method: keys():返回字典dict的键列表
For example,
| 1 2 3 4 5 | for name in favorite_languages.keys(): print(name.title() + ".") But if we use for name in favorite_languages: print(name.title() + ".") |
They all have same output.
n Ergodic all values
n Method: values():返回字典dict的值列表
As we all know, the list of value may have same values, then ,how to keep only one value?
We can use set(). For example,
| 1 2 | for language in set(favorite_languages.values()): print(language.title()) |
n Nesting: 将一系列字典存储在列表中，或将列表作为值存储在字典中，这被称为嵌套。
