Python dictionary key error

In this Python tutorial, we will study How to solve Python dictionary key errors using some examples in python. Moreover, we will also cover these topics.

• Python dictionary key error handling
• Python dictionary key error but key exists
• Python dictionary key error 0
• Python dictionary key error string
• Python defaultdict key error
• Python dict key error none
• Python dict remove key without error
• Python dictionary try except key error
• Python key error nested dictionary

Python dictionary key error

• In this section, we will discuss what is a key error in the Python dictionary.
• In Python key error is raised when the key does not exist in the dictionary that is used to look up the value.
• For example, suppose you have a dictionary that contains key-value pair within the curly brackets and now if you want to get the particular key from the dictionary which does not exist in the given dictionary then it will raise an error.
• To solve this problem, you can select that item from a dictionary that does exist and you can also handle it by using try-except block.

Example:

my_dict={'U.S.A':15,'France':18,'China':27}

result=my_dict['Japan']
print(result)

In the following given code, we have created a dictionary named ‘my_dict’ that contains elements in the form of key-value pair and then we declared a variable ‘result’ and assign a key element ‘Japan’.

Here is the Screenshot of the following given code.

As you can see in the Screenshot the output displays the keyerror:’japan’ the reason behind this is the key does not exist in the dictionary and it cannot return any value.

Solution

Let’s have a look at the solution to this error by using the get() method

• In Python, the get() method is used to remove the key error and it will check the condition if the key is found then the value is returned, if not then it will raise an error.
• This method is used to retrieve a value from the dictionary and it takes two parameters that indicate the key which we want to be searched and the default value is none.

Syntax:

Here is the Syntax of Python get() method

dict.get(key[,value])

Example:

Let’s take an example and check how to solve this key error

Source Code:

my_dict={'U.S.A':15,'France':18,'China':27}

result=my_dict.get('japan',14)
print("Return value:",result)

Here is the execution of the following given code

As you can see in the Screenshot the output displays the return value is 14.

Also, check: Python Dictionary duplicate keys

Python dictionary key error handling

• In this Program, we will discuss how to solve the key-error problem by using exception handling in Python.
• In Python when your program raises an error or something goes wrong then the try-except method will help the user to catch and handle exceptions.

Example:

Let’s take an example and check how to raise the key error in Python by using handling

my_dictionary = {"George" : 678, "Oliva" : 897, "James" : 156}
  
try:  
  print (my_dictionary["Micheal"])  
except:  
  print ("key error:Key does not contain in dictionary")    

In this example, we have created a dictionary that contains elements in the form of key-value pair and then use the try-except block. This method will check the condition if the key is available in the dictionary then it will display the value of that key and if the key is not available then it will display the message ‘key does not contain in the dictionary’.

Here is the implementation of the following given code.

Solution:

Let’s have a look at the solution to this error

Source Code:

my_dictionary = {"George" : 678, "Oliva" : 897, "James" : 156}

try:  
  print (my_dictionary["Oliva"])  
except:  
  print ("key error:Key does not contain in dictionary")  

In the above code, we have created a dictionary named ‘my_dictionary’ and then we used the handling concept try-except which means if the ‘oliva’ key is available in a dictionary then it will return the value.

Here is the execution of the following given code

As you can see in the Screenshot the output displays the key value that is ‘897‘.

Read: Get First Key in dictionary Python

Python dictionary key error but key exists

• In this section, we will discuss how to solve the key error but key exists in dictionary Python.
• To perform this particular task, first, we will create a dictionary by using curly brackets and the elements are separated by commas.
• To get the key error we are going to use the Python in operator and this operand will check the condition whether a key element is available in the dictionary or not.

Example:

country_name = {'U.S.A':178, 'France':456, 'China':754, 'Australia':345}

 
if 'Germany' in country_name:
    print("Key exist in dictionary")
else:
    print("Key error: Does not contain in dictionary") 

In the above code, we have checked if the ‘Germany’ key exists in a dictionary or not. To do this task first we set the condition if the ‘Germany’ key exists in the dictionary then it will return a value otherwise it will display ‘Key-error’.

Here is the implementation of the following given code.

Read: Python dictionary increment value

Python dictionary key error 0

• In this Program, we will discuss how to solve the key error in the Python dictionary.
• To do this task, we are going to use the indexing method and it is an easy way to get a dictionary key value.
• Let’s take an example and we will see how dictionary indexing works and it will also check whether the key is available in a dictionary or not.

Example:

my_dictionary= {16: 'Germany', 19: 'Japan'} 

print(my_dictionary[0]) 

Here is the execution of the following given code

As you can see in the Screenshot the output displays the key error 0 which means it does not locate the key-value and returns the 0 value.

Let’s have a look at the Solution to this error.

Solution:

my_dictionary= {0: 'Germany', 19: 'Japan'} 

print(my_dictionary[0]) 

In the above code, we have updated the given dictionary ‘my_dictionary’ which means we assigned the key as 0 in the dictionary and set the value ‘Germany’. Once you will execute this code the output displays the ‘Germany’ value.

Here is the Screenshot of the following given code

Read: Python dictionary of lists

Python dictionary key error string

• In this Program, we will discuss how to solve the key error string in the Python dictionary.
• In this example, we are going to use the indexing method to get the key error string.
• To do this task, we will assign the unknown key in the list which is not present in the given dictionary.

Example:

my_dictionary = {'z':178,'y':785,'v':345}

print(my_dictionary['m'])

Here is the Output of the following given code.

As you can see in the screenshot, the output displays the key error which means the key string does not exist in the dictionary.

Solution:

Let’s have a look at the solution to this error.

Example:

my_dictionary = {'z':178,'y':785,'v':345}

print(my_dictionary['y'])

In the above code, we have mentioned the key ‘y’ in the list which is available in the given dictionary. Once you will execute this code it will return the value of that specific key.

Here is the implementation of the following given code.

Read: Python dictionary extend

Python defaultdict key error

In Python defaultdict, it will never generate a key error. Suppose you have a dictionary and now you want to exist a new key by using the default dict method and it takes no arguments, generates a default value for a nonexistent key.

Example:

from collections import defaultdict

my_dict = defaultdict(int)
print(my_dict[4])

Here is the Screenshot of the following given code.

Read: Python dictionary multiple keys

Python dict key error none

• In this section, we will discuss how to get the key error none value in Python dictionary.
• To perform this particular task we are going to use the dict.get() method. In Python, the get() method is used to remove the key error and it will check the condition if the key is found then the value is returned, if not then it will raise an error.

Syntax:

Here is the Syntax of the dictionary.get() method.

dict.get(key[,value])

Example:

my_dict={'a':12,'b':45}

new_result = my_dict.get('c')
print("Key error:",new_result)

Here is the Screenshot of the following given code.

As you can see in the screenshot, the output displays the key error None.

Solution:

my_dict={'a':12,'b':45}

new_result = my_dict.get('a')
print(new_result)

In the following given, code we have created a dictionary named ‘my_dict’ that contains elements in the form of key-value pairs. After that, we used the dict.get() method and assign the key element which is available in the dictionary.

Here is the implementation of the following given code.

As you can see in the screenshot, the output displays the return value of a specific key.

Read: How to create an empty Python dictionary

Python dict remove key without error

• In this Program, we will remove a key from Python dictionary without error.
• To do this task we are going to use the dict.pop() method and it will remove a specific key from dictionary and retuirn its value.
• To get the more information regarding dict.pop() method. You can refer our detail article on Python dictionary pop.

Example:

new_dictionary = {'U.S.A':456,'China':123,'Germany':975}

new_result = new_dictionary.pop('China')
print(new_result)
print("After removing the key:",new_dictionary)

You can refer to the below Screenshot.

As you can see in the Screenshot the output displays the ‘China’ key has been removed from the dictionary.

Read: Python Dictionary to CSV

Python dictionary try except key error

• In this section, we will discuss how to use the try-except block in the Python dictionary and get the key error.
• In Python, try-except block checks the statement if the code does not execute successfully then the program will end at the line and it generates the error while in case of except code will successfully run.
• In this example, we will create a dictionary that contains elements in the form of key-value pair and then we will use the try-except block. This method will check the condition if the key is available in the dictionary then it will display the value of that key
• And if the key is not available then it will display the message ‘key does not contain in the dictionary.

Example:

new_dict = {"U.S.A" : 156, "China" : 2356, "Germany" : 897}
  
try:  
  print (new_dict["Japan"])  
except:  
  print ("key error:Key does not contain in dictionary")  

Here is the Screenshot of the following given code.

Solution:

Let’s have a look at the solution to this error.

Source Code:

new_dict = {"U.S.A" : 156, "China" : 2356, "Germany" : 897}
  
try:  
  print (new_dict["Germany"])  
except:  
  print ("key error:Key does not contain in dictionary")  

Here is the implementation of the following given code

Read: Python dictionary of tuples

Python key error nested dictionary

• Here we are going to discuss how to solve the key error in Python nested dictionary.
• To do this task first we will create a nested dictionary and assign multiple dictionaries. Next, we will use the dict.get() method and this method will help the user to remove the key error and it will check the condition if the key is found then the value is returned, if not then it will raise an error.

Example:

my_dict = { 'Country_name': {'Germany': 678},
                'Desgination': {'Developer': 987}}
new_result = my_dict.get('Number')
print("Key error:",new_result)

In the above code, we have used the dict.get() method and within this function, we have assigned the unknown key element. Once you will execute this code the output displays the key error value ‘None’ which means the key we have assigned in an argument is not present in the given dictionary.

Here is the Screenshot of the following given code.

Solution:

Let’s have a look at the solution to this error.

my_dict = { 'Country_name': {'Germany': 678},
                'Desgination': {'Developer': 987}}
new_result = my_dict.get('Country_name')
print(new_result)

In the above code, we have updated the dict.get() function. In this example, we have assigned the present key which is available in the given dictionary as an argument. Once you will execute this code it will return the value.

You may also like to check the following python tutorials.

• Python dictionary contains + examples
• Python dictionary comprehension
• Python Dictionary Search by value
• Python dictionary initialize
• Python dictionary update() method [With Examples]
• Python dictionary multiple values
• Python convert dictionary to list

So, in this tutorial, we have learned How to solve Python dictionary key errors using some examples in python. Additionally, we have also covered these topics.

• Python dictionary key error handling
• Python dictionary key error but key exists
• Python dictionary key error 0
• Python dictionary key error string
• Python defaultdict key error
• Python dict key error none
• Python dict remove key without error
• Python dictionary try except key error
• Python key error nested dictionary