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How Can I Access a Predefined List Based on a String Input in Python?

Susan Sarandon
Release: 2024-12-18 20:42:17
Original
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How Can I Access a Predefined List Based on a String Input in Python?

Accessing Variables by String Name

Problem:

You desire a function that returns a predefined list based on a string input. For instance, given a string "audio," the function should output the list ['mp3', 'wav'].

Easiest Solution with a Dictionary:

A standard dictionary can fulfill this requirement effortlessly.

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get_ext = {'text': ['txt', 'doc'],

           'audio': ['mp3', 'wav'],

           'video': ['mp4', 'mkv']

}

 

get_ext['video']  # Returns ['mp4', 'mkv']

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Using Functions:

For more advanced applications, utilizing functions might be preferred.

Assigning a Dictionary's Get Method:

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get_ext = get_ext.get

 

get_ext('video')  # Returns ['mp4', 'mkv']

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Wrapping a Dictionary Inside a Function:

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def get_ext(file_type):

    types = {'text': ['txt', 'doc'],

             'audio': ['mp3', 'wav'],

             'video': ['mp4', 'mkv']

    }

 

    return types.get(file_type, [])

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Creating a Custom Class for Extensibility:

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class get_ext(object):

    def __init__(self):

        self.types = {'text': ['txt', 'doc'],

                      'audio': ['mp3', 'wav'],

                      'video': ['mp4', 'mkv']

        }

 

    def __call__(self, file_type):

        return self.types.get(file_type, [])

 

get_ext = get_ext()

 

get_ext('audio')  # Returns ['mp3', 'wav']

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This allows you to modify file types dynamically.

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get_ext.types['binary'] = ['bin', 'exe']

 

get_ext('binary')  # Returns ['bin', 'exe']

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