Python Design Patterns 简明教程
Python Design Patterns - Dictionaries
字典是包含键值组合的数据结构。这些已广泛用于 JSON - JavaScript 对象表示法。字典用于 API（应用程序编程接口）编程。字典将一组对象映射到另一组对象。字典是可变的；这意味着可以根据需要随时更改它们。
How to implement dictionaries in Python?
以下程序展示了 Python 中字典的基本实现，从创建到实现。
# Create a new dictionary
d = dict() # or d = {}
# Add a key - value pairs to dictionary
d['xyz'] = 123
d['abc'] = 345
# print the whole dictionary
print(d)
# print only the keys
print(d.keys())
# print only values
print(d.values())
# iterate over dictionary
for i in d :
print("%s %d" %(i, d[i]))
# another method of iteration
for index, value in enumerate(d):
print (index, value , d[value])
# check if key exist 23. Python Data Structure –print('xyz' in d)
# delete the key-value pair
del d['xyz']
# check again
print("xyz" in d)