#Python Lists

Lists are used to store multiple items in a single variable. They are one of four built-in data types in Python used to store collections of data; the other three are Tuple, Set, and Dictionary, each with different qualities and usage.

Lists are created using square brackets:

pythoncopymylist = ["apple", "banana", "cherry"]

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#List Items

List items are ordered, changeable, and allow duplicate values. They are indexed, starting from [0].

#Key Characteristics

• Ordered: Items have a defined order that will not change. If you add new items, they are placed at the end of the list.
• Changeable: You can change, add, and remove items after the list has been created.
• Allow Duplicates: Because items are indexed, lists can have multiple items with the same value.

pythoncopy# Example: Lists allow duplicate values
thislist = ["apple", "banana", "cherry", "apple", "cherry"]
print(thislist)

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#Essential Operations

#List Length

To determine how many items a list has, use the len() function:

pythoncopythislist = ["apple", "banana", "cherry"]
print(len(thislist)) # Output: 3

#Data Types

List items can be of any data type, and a single list can contain mixed data types:

pythoncopylist1 = ["abc", 34, True, 40, "male"]

#The type() Function

From Python's perspective, lists are defined as objects with the data type 'list':

pythoncopymylist = ["apple", "banana", "cherry"]
print(type(mylist)) # Output: <class 'list'>

#The list() Constructor

You can also use the list() constructor to create a list. Note the use of double round brackets:

pythoncopythislist = list(("apple", "banana", "cherry"))
print(thislist)

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#Python Collections (Arrays)

When choosing a collection type, it is useful to understand the specific properties of each:

\* Note on Sets: Set items are unchangeable, but you can remove and/or add items.

\\ Note on Dictionaries: As of Python 3.7, dictionaries are ordered. In Python 3.6 and earlier, they are unordered.