Python Function To Check If A Key Exists In Dictionary

There are multiple ways to see if key exists in Python dictionary or not, like using keys(), has_key(), get(), Try and Except.

To me Try and Except is a best and more efficient way in python to check if a key exists in dictionary because it provides an appropriate way of handling unexpected errors without interrupting the code flow.

Now I'm sharing a code snippet showing the way to use Try and Except block to check a key in Python dictionary.

In this code, I have created one function "key_check" which basically accepts a dictionary and a key where we will check the existence of a key in that dictionary.

If the key is present in the dictionary this function will return true else false.

For example: for Key='Name'. This function will return true and print 'Name' exists. 

def key_check(mydict, key):
    #Python function to check if key in dictionary already exists
    try:
       mydict[key]
       return True
    except KeyError:
        return False

def main():
    
    #createing a dictionary 
    mydict = {
        "Name": "Python",
        "Hello": "World",
        "Version": 3
    }
    
    # key to check
    key = 'Name'
    
    print('calling key check function in if block')
    
    if key_check(mydict, key):
        print("'%s' exists"%key)
    else:
        print("'%s' does not exists"%key)

if __name__ == '__main__':
    main()

I hope that you find this helpful.