Python内置字典,dict全称dictionary,在其他语言中称为map,使用键值对(key-value),具有极快的查找速度 如果用dict实现,只需要一个“名字”-“成绩”的对照表,直接根据名字查找成绩,无论这个表有多大,查找速度都不会变慢。用Python写一个dict如下: >>> d = {'Michael': 95, 'Bob': 75, 'Tracy': 85} >>...
value =Nonefordicinx:ifdic['name'] =='goals': value =int(dic['value'])break The listxis a stats for a football player. So, a player that have not scored any goal will not have a dictionary withdic['name']is'goals'. playerStats = [...], each element inplayerStatshas similar ...
Python: Nested dictionaries: getting string(key+value) as values then swap with keys, combining dictionaries 0 Replace nested keys in a dictionary with values of another dictionary 1 Pythonic way of switching nested dictionary keys with nested values 2 Retrieve and replace value in a dict...
3' } # 查找值并输出新值 key = 'key2' if key in lookup_table: new_value = lookup_table[key] print("新值为:", new_value) else: print("键不存在") # 使用get()方法查找值并输出新值 key = 'key4' new_value = lookup_table.get(key, "键不存在") print("新值为:", new_va...
File "<stdin>", line 5, in reverse_lookup LookupError 1. 2. 3. 4. 5. 你触发的异常和Python触发的产生效果一样:都打印一条回溯和错误信息。 raise语句接受一个详细的错误信息作为可选的实参。 例如: >>> raise LookupError('value does not appear in the dictionary') ...
Python学习-dictionary字典 dictionary的遍历是对key的遍历,key的选择顺序是无序的: 1 2 3 defprint_hist(h): forcinh: printc, h[c] dict反向查找并抛出异常: 1 2 3 4 5 defreverse_lookup(d, v): forkind: ifd[k]==v: returnk raiseValueError,'找不到元素'...
您可以这样做:#Just an example how the dictionary may look likemyDict = {'age': ['12'], '...
7. 反向查詢: 由 Value 去查詢 Key >>> def reverse_lookup(d,v): ... for k in d: ... if d[k] == v: ... return k ... raise LookupError() ... >>> X = {1:'one',2:'two',3:'three',4:'four',5:'five'} >>> k = reverse_lookup(X,'two') ...
通过setattr 把原字典的key:value以value:key的形式放到lookupdict的__dict__中,这样就可以直接使用get方法获取值对应的键。 Tips __getitem__ 函数是 look_code["not_found"] 是这种情况下调用的。 __getattribute__ 是 look_code.not_found 情况下调用的。
dictionary = { "apple": "苹果", "banana": "香蕉", "cat": "猫" } 接下来,我们可以编写一个函数来实现用户输入单词并返回其对应的意思。这个函数可以使用字典的get()方法来查找单词的意思。如果找不到对应的意思,函数会返回一个默认值。 def lookup_word(word): ...