In this article, we will learn how to Fix “Key Error: 0” Python with a Dictionary All the data types can hold only one single value as an element. Instead, the concept of a dictionary in Python is introduced as the random collection of values that can store data values in pairs in the form of a map.

The values in pair are the key values and it makes this data type more efficient.

A common error that people often get when they are trying to use a dictionary in Python is “KeyError: 0”. This means there was no match found for whatever key was used, even though it may have existed on the other end!

The most common cause of this message being displayed stems from something called “Has Axis”, which allows keys within lists or dictionaries itself to be indexed differently than normal accordingly putting more strain onto search algorithms so as long as you don’t mind creating an unfairly.

What is a “Key Error: 0” Python with a Dictionary?

• The key error it’s a type of runtime error that occurs when a key cannot be located in a dictionary
• Dictionary: The term “dictionary” refers to an unsorted collection of objects that deal with data type keys.
• They are also known as associative arrays and are Python’s version of data structures.
• They’re made up of key-value pairs, with each pair mapping the key to its corresponding value.

The term dictionary in python functions is the same as that of a normal dictionary and it is the most common mapping in python.

The key values are unique and absolute data types that include strings and integers that refer to a number. A python error means the key you are trying to find is not present in the given data type.

So, if you try to access an element using a key but this value is not in the range of values available in the dictionary then python will raise the term “KeyError:[key]”. KeyError means that we are trying to access key 0 from the dictionary where the key is not present.

To get rid of this issue, you have to check that the key is present in the range of values available in a dictionary before using the data types. Here are some methods you can use to fix this issue,

Method 1: By the Use of ‘in’ operator

The use of the ‘in’ operator can fix the issue of KeyError.

For example

d = {1:3, 3:6}

for i in range (1, 5):
	if i in d:
		print (d[i])

Or, it will print any other option you want to perform.

Output is

3
6

Here we have to access a key in a range of 1-5 where 2 and 4 are not available in the dictionary and that’s how the program proceeds.

Method 2: By the Use of Try-Except Block Method:

The try-except block method can be used to fix the key error.

For example:

d = {1:3, 3:6}

for i in range (1,5):
	try:
		print(d[i])
	except KeyError:
		continue

Output is

3
6

Here we get no error because the use of ‘continue’ helps to perform the ‘for’ loop on getting key error.

If we place the try block out of the ‘for’ loop we can catch the error again and the flow of the program stops.

Method 3: By Using Get Method:

You can fix KeyError: 0 by using the get method.

d = {1:1, 2:2}

print(d.get(0, -1))

You can use the ‘get’ method that returns the default value instead of causing a rise in the error.

In the above example, the dictionary d doesn’t have key 0, so it will return -1 which is passed as the second parameter in the get method.

And if you do not pass the second parameter it will give none as output.

d= {1:3, 3:6}

try:
	for i in range (1,5):
		print([d[i]])
except KeyError:
	print("ERROR")

Output:

[3]

ERROR

Here 2 is not present as a key in a dictionary and thus the program is terminated.

You can also read more: TypeError: Must be str, not tuple in Python

Method 4: By the Use of Exception Handling:

We will see that when 0 is not present in the dictionary then we cannot get a 0 key in return.

For example,

dict_1 = {1: "One", 2: "Two", 3: "Three", 4: "Four"}

for i in range (5):
	try:
		print (dict_1[i])
	except KeyError:
		print("Key "+str(i)+" does not exist in the dictory")

Output

Key 0 does not exist in the dictionary

One

Two

Three

Four

Method 5:

The simple of all the methods is that you can simply enter the 0 in the dictionary.

d = {1:1, 2:2}

try:
	print(d[0])
except KeyError:
	print("Error")

Output

Error

In this way, you can easily handle the error.

How to solve KeyError when Key exists

You’re getting a KeyError because you’re trying to access a key that doesn’t exist in the dictionary. This can happen if you misspell the key name, or if the key name is deleted from the dictionary.

One way to avoid this error is to use the get() method instead of using square brackets to access keys. The get() method will return None if the key doesn’t exist, instead of raising a KeyError.