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 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.

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 very unique and absolute data types that include strings and integers which 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 is in d,

print (d[i])

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

Output is 3 and 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 : 0

continue

Output is 3 and 6.

By the Use of Try-Except Block Method

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}

d.get(0, -1)

KeyError: 0

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

Key Error: 0” Python with a Dictionary

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 for 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: “One”, 2: “Two”, 3: “Three”, 4: “Four”}

For i in range (5):

try:

print (dict[i])

Except KeyError:

Print(“Key”“+str(i)+”does not exist in dictionary”)

Output

Key ‘0’ does not exist in the dictionary

One

Two

Three

Four

Key ‘0’ does not exist in the dictionary

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:

d[0]

except KeyError:

Fix “Key Error: 0” Python with a Dictionary

In this way, you can easily handle the error.

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