Python provides the dictionary type in order to store key and value pairs. The key is used to identify the value part which is very similar to the real-life dictionary. The key is used to search, find and match specific data and return its value. The dictionary data type provides the has_key() method in order to check if the specified key exists.
has_key() Method Syntax
The has_key() method is provided in Python2 and can not be used in Python3. The has_key() method has the following syntax.
DICTIONARY.has_key(KEY)- DICTIONARY is the dictionary where the KEY is checked for. This is required.
- KEY is the key we want to check in DICTIONARY. This parameter is required.
If the specified key exist int the dictionary the has_key() method returns True if not it returns False.
Check Specified Key Exist In Dictionary
The has_key() method can be used to check if the specified key exist in the specified dictionary. The has_key() method only available for the Pyhon2.
names = {'1':'İsmail' , '2':'Ahmet' , '3':'Ali'}
print(names.has_key('1'))
print(names.has_key('5'))True False
If you try to use has_key() method in Python3 you will get an error like below. Simply it express that the dict object to not contains ‘has_key()’ method.
AttributeError: 'dict' object has no attribute 'has_key'has_key() Method Alternative In Python3
As Python version 3 the has_key() method is not supported. If you try to use we will get an error which is described error. But Python 3 provides more elegant and pythonic way in order to check if the specified key exist in a dictionary. The in operator can be used to in order to check a key existince in a dictionary. In the following example we will check if the key ‘1’ exist in the dictionary named names.
names = {'1':'İsmail' , '2':'Ahmet' , '3':'Ali'}
print('1' in names)
print('5' in names)If the specified key exist the check returns True and if not returns False.
True False