In this Python program, we will learn how to check if a given key exists in a dictionary or not. There are various ways to do this. In this program, we used the python dictionary built-in keys() and get() functions and without using any built-in function.
Here is the source code of the program to check if a given key exists in a dictionary or not.
In this program, we used the python dictionary built-in key() function, and the key() method in Python dictionary returns a view object that displays a list of all the keys in the dictionary.
# Python Program to check if a Given key exists in a Dictionary Using keys() method
# Dictionary
myDict = {'a': 'apple', 'b': 'Banana' , 'o': 'Orange', 'g': 'Guava'}
# Print Dictionary
print("Dictionary: ", myDict)
# Take the Input From the User
key = input("Enter the Key You Want to Search for: ")
# Check Whether the Given key exists in a Dictionary or Not
if key in myDict.keys():
print("\nKey Exists in the Given Dictionary")
print("Key = ", key, " and Value = ", myDict[key])
else:
print("\nKey Does not Exist in the Given Dictionary")
Dictionary: {'a': 'apple', 'b': 'Banana', 'o': 'Orange', 'g': 'Guava'}
Enter the Key You Want to Search for: o
Key Exists in the Given Dictionary
Key = o and Value = Orange
Dictionary: {'a': 'apple', 'b': 'Banana', 'o': 'Orange', 'g': 'Guava'}
Enter the Key You Want to Search for: p
Key Does not Exist in the Given Dictionary
# Another approach to check if the given key is present in a dictionary or not.
# Dictionary
myDict = {'a': 'apple', 'b': 'Banana' , 'o': 'Orange', 'g': 'Guava'}
# Print the Dictionary
print("Dictionary : ", myDict)
key = input("Enter the Key you want to search for: ")
# Check Whether the Given key exists in a Dictionary or Not
if key in myDict:
print("\nKey Exists in the Given Dictionary")
print("Key = ", key, " and Value = ", myDict[key])
else:
print("\nKey Does not Exist in the Given Dictionary")
Dictionary : {'a': 'apple', 'b': 'Banana', 'o': 'Orange', 'g': 'Guava'}
Enter the Key you want to search for: b
Key Exists in the Given Dictionary
Key = b and Value = Banana
Dictionary : {'a': 'apple', 'b': 'Banana', 'o': 'Orange', 'g': 'Guava'}
Enter the Key you want to search for: t
Key Does not Exist in this Dictionary
In this program, we used the python dictionary built-in get() function and this method return the value for the given key if present in the dictionary. If not, then it will return None (Note: if get() function is used with only one argument).
# Python Program to check if a Given key exists in a Dictionary
# Using dictionary.get() method
# Dictionary
myDict = {'a': 'apple', 'b': 'Banana' , 'o': 'Orange', 'g': 'Guava'}
# Print the Dictionary
print("Dictionary : ", myDict)
key = input("Enter the Key you want to search for: ")
# Check Whether the Given key exists in a Dictionary or Not
if myDict.get(key) != None:
print("\nKey Exists in this Dictionary")
print("Key = ", key, " and Value = ", myDict[key])
else:
print("\nKey Does not Exist in this Dictionary")
Dictionary: {'a': 'apple', 'b': 'Banana', 'o': 'Orange', 'g': 'Guava'}
Enter the Key You Want to Search for: u
Key Does not Exist in the Given Dictionary
Dictionary : {'a': 'apple', 'b': 'Banana', 'o': 'Orange', 'g': 'Guava'}
Enter the Key you want to search for: a
Key Exists in the Given Dictionary
Key = a and Value = apple
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