# Python¶

## Lists, Tuples and Dictionaries¶

The next basic data type is the Python list. A list is an ordered collection of elements, and these elements can be of arbitrary type. Lists are mutable, meaning they can be changed in-place. In python lists are indicated by square brackets [ and ]. Items in a list are indexed starting with 0.

List Basics

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You can even have lists of lists:

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Use multiple indexes for lists within lists

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Index from the end of the list

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Append an item to a list

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Reference multiple items in a list

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Open ended indexes go to the ends of lists

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### Python tuples¶

Tuples are similar to lists, except that they are immutable, meaning that they cannot be changed in place. Tuples are indicated by parenthesis ( and ).

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#### Python dictionaries¶

Dictionaries are unordered collections of key-value pairs. Dictionaries can use various types for keys (e.g. strings, ints) so long as the key is immutable. Values are looked up by key. In python dictionaries are indicated by curly braces { }

Create a dictionary

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Lookup value with key

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Change a value for a key

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Get all keys in dictionary

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Get all values in dictionary

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Check if key exists

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