从Python 字典中删除键值
时间:2020-02-23 14:43:45 来源:igfitidea点击:
在本教程中,我们将看到如何从Python中的字典中删除键。
有多种方法可以做到这一点.Llet探索从字典中删除密钥的不同方式。
使用POP方法
我们可以使用pop方法从字典中删除键。
这是从字典中删除密钥的最佳方法。
countryDict={"Netherlands":"Amsterdam","China":"Beijing","Australia":"Canberra","UK":"London"} print("countryDict before pop:",countryDict) removedCapital=countryDict.pop("China") print("countryDict after pop:",countryDict) print("Removed capital:",removedCapital) #If you try to remove key which is not present in the key, then it will raise KeyError removedCountry=countryDict.pop("USA")
输出:
countryDict before pop: {'Netherlands': 'Amsterdam', 'China': 'Beijing', 'Australia': 'Canberra', 'UK': 'London'} countryDict after pop: {'Netherlands': 'Amsterdam', 'Australia': 'Canberra', 'UK': 'London'} Removed capital: Beijing ————————————————————————— KeyError Traceback (most recent call last) in () 6 7 #If you try to remove key which is not present in the key, then it will raise KeyError —-> 8 removedCountry=countryDict.pop(“USA") 9 KeyError: 'USA'
正如我们可以看到的,当我们成功地从字典中删除关键"China"时,但是当我们尝试删除在字典中不存在的键时,我们就会获得KeyError。
如果将默认值传递给Pop方法,那么我们赢了g get keyerror。
countryDict={"Netherlands":"Amsterdam","China":"Beijing","Australia":"Canberra","UK":"London"} print("countryDict before pop:",countryDict) removedCapital=countryDict.pop("USA","Dummy") print("countryDict after pop:",countryDict)
输出:
countryDict before pop: {'Netherlands': 'Amsterdam', 'China': 'Beijing', 'Australia': 'Canberra', 'UK': 'London'} countryDict after pop: {'Netherlands': 'Amsterdam', 'China': 'Beijing', 'Australia': 'Canberra', 'UK': 'London'}
正如我们所看到的,当我们向POP方法提供默认值时,我们没有得到KeyError并且Dict没有改变。
使用del运算符
我们还可以使用Del运算符从字典中删除密钥。
让我们通过示例来理解。
countryDict={"Netherlands":"Amsterdam","China":"Beijing","Australia":"Canberra","UK":"London"} print("countryDict before removing key china:",countryDict) if 'China' in countryDict: del countryDict['China'] print("countryDict after removing key china:",countryDict)
输出:
countryDict before removing key china: {'Netherlands': 'Amsterdam', 'China': 'Beijing', 'Australia': 'Canberra', 'UK': 'London'} countryDict adter removing key china: {'Netherlands': 'Amsterdam', 'Australia': 'Canberra', 'UK': 'London'}