How To Find A Value In A Dictionary Python

In this tutorial, we will learn about finding a value in a Python dictionary. Dictionaries are one of the most useful data structures provided by Python, which allows us to store a collection of key-value pairs.

Dictionaries provide quick and efficient access to finding values associated with their respective keys.

Step 1: Create a Dictionary

Let us start by creating a simple dictionary with some key-value pairs. You can create a dictionary by placing a comma-separated list of key-value pairs within curly braces {}. A key and its corresponding value are separated by a colon :.

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employee = {
    'name': 'John Doe',
    'age': 30,
    'department': 'Software Engineering',
    'email': '[email protected]'
}

Step 2: Access the Value Using Key

In most cases, you will access a value in a dictionary by providing its key within square brackets [].

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value = employee['age']
print(value)
 
30

If you try to access a key that does not exist in the dictionary, you will get a KeyError.

Step 3: Using the get() Method

Alternatively, you can use the get() method to retrieve a value associated with a key. The advantage of using the get() method over the square bracket notation is that it does not raise a KeyError if the key does not exist in the dictionary. Instead, it returns None or any default value specified as a second argument.

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value = employee.get('salary')
print(value)
 
None

You can also provide a default value as the second argument, which will be returned if the key does not exist.

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value = employee.get('salary', 'Not Provided')
print(value)
 
Not Provided

Step 4: Checking If a Key or Value exists in the Dictionary

You can use the in keyword to check if a key exists in a dictionary. This method returns a boolean value, True if the key exists and False otherwise.

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key_exists = 'age' in employee
print(key_exists)
 
True

To check if a value exists in the dictionary, you can use the values() method. The values() method returns a view object that displays a list of all the values in the dictionary.

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value_exists = 'Software Engineering' in employee.values()
print(value_exists)
 
True

Full Code

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employee = {
    'name': 'John Doe',
    'age': 30,
    'department': 'Software Engineering',
    'email': '[email protected]'
}
 
value = employee['age']
print(value)
 
value = employee.get('salary')
print(value)
 
value = employee.get('salary', 'Not Provided')
print(value)
 
key_exists = 'age' in employee
print(key_exists)
 
value_exists = 'Software Engineering' in employee.values()
print(value_exists)

Conclusion

In this tutorial, we have learned how to find a value in a Python dictionary using various approaches, such as accessing the value using a key, using the get() method, and checking if a key or value exists in the dictionary using the in keyword. These methods provide a convenient way to work with dictionaries and greatly enhance their usability.