Remove Multiple keys from Python Dictionary

How to remove multiple keys from Python Dictionary? To remove multiple keys you have to create a list or set with the keys you want to delete from a dictionary and iterate it and use either the del keyword or the pop() function to delete each key from the list.

In this article, I will explain the del keyword, pop() function, dictionary comprehension, and for loop to remove the specified multiple keys from the dictionary with examples.

1. Quick Examples of Remove Multiple Keys from Dictionary

Following are quick examples of removing multiple keys from the Dictionary.


# Below are the quick examples

# Example 1: Remove multiple keys using del keyword
keys_list = ['fee', 'discount', 'course']
for key in keys_list:
	del my_dict[key]

# Example 2:  Use pop() & list comprehension to
# remove multiple keys from dictionary
keys_list = ['fee', 'discount', 'course']
[my_dict.pop(key) for key in keys_list]

# Example 3: Remove multiple keys from dictionary 
my_dict = {key: my_dict[key] for key in my_dict if key not in keys_list}

# Example 4: Using items()along with list comprehension & dict()
# Remove multiple keys from dictionary
my_dict = dict([(key, val) for key, val in
		my_dict.items() if key not in keys_list])

# Example 5: Remove multiple keys using for loop
print("Before removing the key:\n", my_dict)
keys_list = ["course", "duration"]
for key in keys_list:
    del my_dict[key]

# Example 6:  Remove all keys using clear()
my_dict = {'course':'python','fee':4000,'duration':'60days'}
# empty the dictionary 
my_dict.clear()
print("Length", len(my_dict))

# Example 7: Remove all keys using del 
my_dict = {'course':'python','fee':4000,'duration':'60days'}

2. What is Python Dictionary

A Python dictionary is a collection that is unordered, mutable, and does not allow duplicates. Each element in the dictionary is in the form of key:value pairs. Dictionary elements should be enclosed with {} and key: value pair separated by commas. The dictionaries are indexed by keys.

Moreover, dictionaries are mutable data types, which means that you can be added, deleted, and updated their key:value pairs. keys are an immutable type such as string, numbers(int, float), and tuple. In case, you add duplicates, it will update the existing key with the new value.

Let’s create a Python dictionary,


# Create dictionary
my_dict = {'course':'python','fee':4000,'duration':'60days', 'discount:1200}
print(my_dict)

Yields below output.

Python Dictionary

3. Remove Multiple Keys from Dictionary

We can use a del keyword and for loop to remove the multiple keys from the dictionary in Python. First, we have to initialize the list of keys that we want to remove from the dictionary. Then using the del keyword we will remove the list of specified keys from the dictionary with the help of iterating. Here is an example. After removing the specified multiple key, I printed the remaining key-value pairs from the dictionary to the console.


# Create removed keys list
keys_list = ['fee', 'discount', 'course']
print("Before removing the multiple keys: \n", my_dict)

# Remove multiple keys using del keyword and for loop
for key in keys_list:
	del my_dict[key]

# Print 
print("After removing the multiple keys: \n", my_dict)

Yields below output. Note that removing a key actually removes the key and the value associated with it.

Remove multiple keys from Python dictionary

4. Remove Multiple Keys from Dictionary using pop()

The python dictionary pop() function is another method that can be used to remove the keys from the dictionary, this returns the value related to the removed key. If a key does not exist in the dictionary and the default value is specified, then returns the default value; else throws a KeyError.

Note that using the pop() function we can remove the single key at a time, but with the help of list comprehension you can delete multiple keys. Here, list comprehension iterates a list of specified multiple keys and removes them from the dictionary.

Let’s pop the specified key with help of list comprehension to remove list of multiple keys from the Python dictionary.


# Use pop() & list comprehension to
# remove multiple keys from dictionary
# Create removed keys list
keys_list = ['fee', 'discount', 'course']
[my_dict.pop(key) for key in keys_list]

print("After removing the multiple keys: \n", my_dict)

Yields below output.

5. Remove Multiple keys using Dictionary Comprehension

Alternatively, we can use dictionary comprehension along with the if condition and not in operator we can remove specified multiple keys from the dictionary and return a new dictionary that contains the remaining key-value pairs of the dictionary.


# Remove multiple keys from dictionary 
my_dict = {key: my_dict[key] for key in my_dict if key not in keys_list}
print("After removing the multiple keys: \n", my_dict)

# Output:
# After removing the multiple keys: 
# {'duration': '60days'}

6. Remove Multiple keys from Dictionary using items()

Using Python item() function along with dict() function and list comprehension we can also remove multiple keys from the dictionary. In this example, we create a new dictionary using dict() function instead of removal keys and using items() function we can extract key-value pairs and iterate them using list comprehension.


# Using items()along with list comprehension & dict()
# Remove multiple keys from dictionary
my_dict = dict([(key, val) for key, val in
		my_dict.items() if key not in keys_list])

print("After removing the multiple keys: \n", my_dict)

# Output:
# After removing the multiple keys:
# {'duration': '60days'}

7. Remove Multiple Keys using For Loop

We can also delete multiple keys by looping through the dictionary using for loop. It will iterate the list of specified multiple keys from the dictionary and then remove them using the del keyword.


# Remove multiple keys using for loop
print("Before removing the key:\n", my_dict)
keys_list = ["course", "duration"]
for key in keys_list:
    del my_dict[key]
print("After removing the keys:\n", my_dict)

# Output:
# Before removing the key:
#  {'course': 'python', 'fee': 4000, 'duration': '60days'}
# After removing the keys:
#  {'fee': 4000}

8. Remove All Keys using del

Using del keyword we can remove all key-value pairs from a dictionary.


# Remove all keys using del 
my_dict = {'course':'python','fee':4000,'duration':'60days'}

# empty the dictionary 
del my_dict

9. Delete all Keys from Dictionary using clear()

The Python dictionary clear() function is used to remove all key-value pairs from the dictionary. The clear() function doesn’t return any value.


# Remove all keys using clear()
my_dict = {'course':'python','fee':4000,'duration':'60days'}
# empty the dictionary 
my_dict.clear()
print("Length", len(my_dict))
print(my_dict)

# Output:
# Length 0
# {}

10. Conclusion

In this article, I have explained the Python del keyword, pop() function, dict comprehension, and for loop to remove the specified multiple keys from Python dictionary with examples.

Happy learning !!

References

https://docs.python.org/3/tutorial/datastructures.html