Essential Books

Get the unique elements of a list

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Let’s say you’ve got a list of restaurants – maybe you read it from a file. You care about the unique restaurants in the list. The best way to get the unique elements from a list is to turn it into a set: 

restaurants = ["McDonald's", "Burger King", "McDonald's", "Chicken Chicken"]
unique_restaurants = set(restaurants)
print(unique_restaurants)
# prints {'Chicken Chicken', "McDonald's", 'Burger King'}

Note that the set is not in the same order as the original list; that is because sets are unordered, just like dicts.

This can easily be transformed back into a List with Python’s built in list function, giving another list that is the same list as the original but without duplicates: 

list(unique_restaurants)
# ['Chicken Chicken', "McDonald's", 'Burger King']

It’s also common to see this as one line: 

# Removes all duplicates and returns another list
list(set(restaurants))

Now any operations that could be performed on the original list can be done again.

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Set:
* Set
* Operations on sets
* Get the unique elements of a list
* Set of Sets
* Set Operations using Methods and Builtins
* Sets versus multisets
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0 Getting Started
1 List comprehension
2 Filter
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6 Math module
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79 PyInstaller - Distributing Python Code
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116 List destructuring
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118 Mixins
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122 Plugin and Extension Classes
123 Websockets
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154 Audio
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156 queue module
157 ijson
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159 base64 module
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162 Sockets and Message Encryption / Decryption
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164 Input Subset and Output External Data Files using Pandas
165 hashlib
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168 Creating a Windows Service
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170 configparser
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172 Optical Character Recognition OCR
173 Python Data Types
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175 Generating graphs
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177 Functional Programming
178 Python Virtual Environment - virtualenv
179 sys module
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181 virtualenvwrapper on Windows
182 Python Requests Post
183 Plotting with Matplotlib
184 Python Lex-Yacc
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187 pip and PyPI Package Manager
188 Writing to CSV from String or List
189 Raise Custom Errors Exceptions
190 Using loops within functions
191 Contributors