Python cookbook(数据结构与算法)从字典中提取子集的方法示例

# example of extracting a subset from a dictionaryfrom pprint import pprintprices = { 'ACME': 45.23, 'AAPL': 612.78, 'IBM': 205.55, 'HPQ': 37.20, 'FB': 10.75}# Make a dictionary of all prices over 200p1 = { key:value for key, value in prices.items() if value > 200 }print("All prices over 200")pprint(p1)# Make a dictionary of tech stockstech_names = { 'AAPL', 'IBM', 'HPQ', 'MSFT' }p2 = { key:value for key,value in prices.items() if key in tech_names }print("All techs")print(p2)

All prices over 200{'AAPL': 612.78, 'IBM': 205.55}All techs{'AAPL': 612.78, 'HPQ': 37.2, 'IBM': 205.55}