This will return my_dict[key] if key exists in the dictionary, and None otherwise. If the second parameter is not specified (i.e. my_dict.pop('key')) and key does not exist, a KeyError is raised. The following example removes the master key for the AdventureWorks2022 database. USE AdventureWorks2022; If we want to be able to safelyremove a key from a dictionary, meaning that no error is returned, we can pass in a default value into our .pop()method. A good default value would be to return None, as it allows us to simply move on. # Delete a key that doesn't exist using .pop() In the next section, you’ll learn how to remove a key from a Python dictionary using a dictionary comprehension. Use a Python Dictionary Comprehension to Remove a Key from a Dictionary

Now that you have an understanding of how Python dictionary comprehensions work, let’s see how you can use them to delete a key from a dictionary: # Delete a Key using a Dictionary Comprehension If we try to delete a key that doesn’t exist, Python will throw a KeyError. Let’s see how this looks: # Delete a key that doesn't exist using delTo delete a key regardless of whether it is in the dictionary, use the two-argument form of dict.pop(): my_dict.pop('key', None) Python also provides the delkeyword to remove a key from a dictionary. Using the delkeyword is a less safe approach, as there is not way to simply provide a default_value, as you can with the .pop()method. Output: The dictionary before performing remove is : {'Anuradha': 21, 'Haritha': 21, 'Arushi': 22, 'Mani': 21} In this post, you learned how to safely remove keys from a Python dictionary. You learned how to do this using the .pop()method, the delkeyword, and using a dictionary compreghension. Finally, you learned how to safely remove multiple keys from a Python dictionary. Let’s see how we can pass in a list of different keys to delete, including some that don’t exist: # How to remove multiple keys from a Python dictionary

Using the del keyword; it's almost the same approach like you did though - myDict = {'one': 100, 'two': 200, 'three': 300 } Applies to: SQL Server Azure SQL Managed Instance Azure Synapse Analytics Analytics Platform System (PDW) Because the comprehension uses an ifstatement, we can say that this is a safe method of deleting a key from a Python dictionary. How to Remove Multiple Keys from a Python DictionaryPython makes it easy to remove multiple keys from a dictionary. The safest way of doing this is to loop over a list of keys and use the .pop()method.

The auxiliary space required for this code is O(1), as we are only modifying the existing dictionary and not creating any new data structures. Method 2: Remove a Key from a Dictionary using pop() And if you need to catch errors where you pop a value that isn't in the dictionary, use lambda inside map() like this: map(lambda x: myDict.pop(x,None), ['a', 'c', 'e']) Specifically to answer "is there a one line way of doing this?" if 'key' in my_dict: del my_dict['key']I want to remove a key from a dictionary if it is present. I currently use this code: if key in my_dict: If you need to remove a lot of keys from a dictionary in one line of code, I think using map() is quite succinct and Pythonic readable: myDict = {'a':1,'b':2,'c':3,'d':4} Now that you have an understanding of what dictionaries are, let’s see how we can use Python to remove a key from a dictionary. Use Python .pop() to Delete a Key from a Dictionary It took me some time to figure out what exactly my_dict.pop("key", None) is doing. So I'll add this as an answer to save others googling time: pop(key[, default]) The key doesn’t exist and a default value is provided, in which case, the default value is returned.