Python Copy Dict Without One Key

This Python tutorial will teach you about Python copy dict without one key.

I was building the product recommender model and collected a dataset containing different products; some of the columns in the dataset were unnecessary, like the product ID column.

Data was collected in dictionary form, so I wanted to remove unwanted columns like ID as a data processing task. I used the dictionary comprehension to copy the dataset without that key, “ID.”

So, in this tutorial, I have explained how you can copy the dict without a key or some of the keys using the dictionary comprehension and If statement in for loop.

Python Copy Dict Without One Key Using If Condition

To copy a dict except one key, use the If statement with the For loop. Let’s see with an example.

Suppose you have user information in the dictionary as below. {‘name’: ‘James’, ‘age’:30, ‘ ‘city’: ‘New York’, ‘gender’: ‘male’}.

user = {'name': 'James', 'age':30, 'city': 'New York', 'gender': 'male'}

Now, you have to copy the ‘user’ dictionary without the key ‘city’. First, iterate over the dictionary to access each key-value pair, and then, using the If statement, check for the key you don’t want to copy, as shown in the code below.

key_to_exclude = 'city'
new_user ={}
for key, value in user.items():
   if key not in key_to_exclude:
       print(key, value)
print(new_user)
Python Copy Dict Without One Key Using If Condition

Look at the output; the dictionary ‘user’ is copied into the new dictionary ‘new_user’ without the key ‘city’ as you can see in the production {‘name’: ‘James’, ‘age’: 30, ‘gender’: ‘male’}.

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Let’s understand the cod parts. This line key_to_exclude=’city’ is the key you don’t want to copy with a dictionary.

Then new_user = {} is the empty dictionary where the old dictionary will be copied without the key ‘city’.

After that, a for loop starts and iterates over the ‘user’ dictionary’s key-value pairs; the items() method is called on the ‘user’ dictionary to access each key-value pair.

Then, each iteration takes the key from the ‘user’ dictionary and checks if it is not in the variable ‘key_to_exclude’. If it is true, it adds that key and corresponding value in a new dictionary using the new_user[key]=value.

Thus, it copies the dictionary ‘user’ without the key ‘city’ into the dictionary ‘new_user’.

This is how to copy a dict without one key using Python’s for loop and if statement.

How to Copy Python Dict Without Key Using Dictionary Comprehension

So, in the preceding section, you have used the for loop and if statement to copy the dictionary without a key. Here, you will use the same concepts, but instead of running the for loop separately, in Dictionary comprehension, the for loop and if statement is used within curly braces {}.

For example, let’s say you want to copy dict without a key ‘age’ using the dictionary comprehension as shown below.

user = {'name': 'James', 'age':30, 'city': 'New York', 'gender': 'male'}

key_to_exclude = 'age'
new_user ={key:value for key, value in user.items() if key not in key_to_exclude }

print(new_user)
How to Copy Python Dict Without Key Using Dictionary Comprehension

The output shows that the dictionary ‘user’ is copied without a key ‘age’ into a dictionary new_user using dictionary comprehension.

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Try to understand this part ‘new_user ={key:value for key, value in user.items() } if the key is not in key_to_exclude, here within dictionary new_user, iterating over the key-value of ‘user’ using the ‘for key, value in user.items()’.

Then, check that each key doesn’t belong to the key in key_to_exclude if it doesn’t, copy that key and its corresponding values into the new dictionary.


After it iterates over each key value, it returns a new dictionary named ‘new_user’ containing all the keys of the old dictionary except the key ‘age’, as you can see in the output ‘{‘name’: ‘James’, ‘city’: ‘New York’, ‘gender’: ‘male’}’.

Similarly, if you want to know how to copy a dictionary without some keys, you can include the keys into a separate variable as a list you want to remove, then use any of the above methods.

Conclusion

In this Python tutorial, you learned about Python copy dict without one key using the dictionary comprehension and for loop containing the if statement.

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