練習：
假設有一個字典，ages = {
"Peter": 10,
"Isabel": 11,
"Anna": 10,
}，寫成程序找出value=10的key
思路：
根據value查找字典的key
方法一：
1 """ 2 假設有一個字典，ages = { 3 "Peter": 10, 4 "Isabel": 11, 5 "Anna": 10, 6 }，寫成程序找出value=10的key 7 """ 8 9 def func(ages): 10 for key in ages: 11 if ages[key] == 10: 12 print(key) 13 func({ 14 "Peter": 10, 15 "Isabel": 11, 16 "Anna": 10, 17 })
方法二（進一步優化）：
""" 假設有一個字典，ages = { "Peter": 10, "Isabel": 11, "Anna": 10, }，寫成程序找出value=10的key """ def func(ages,value1): for key in ages: if ages[key] == value1: print(key) func({ "Peter": 10, "Isabel": 11, "Anna": 10, },10)
方法三（簡化代碼，return拋出結果）：
def get_keys(d, value): return [k for k,v in d.items() if v == value] print(get_keys(ages,10))