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5.5. Lists

A list is a data structure in Python that can contain multiple elements of any of the other data type. A list is defined with square brackets [ ] and commas , between elements.

>>> lst = [ 1, 2, 3 ]
>>> type(lst)
list

>>> lst = [ 1, 5.3, '3rd_Element']
>>> type(lst)
list

5.5.1. Indexing Lists

Individual elements of a list can be accessed or indexed using bracket [ ] notation. Note that Python lists start with the index zero, not the index 1. For example:

>>> lst = ['statics', 'strengths', 'dynamics']
>>> lst[0]
'statics'

>>> lst[1]
'strengths'

>>> lst[2]
'dynamics'
Remember! Python lists start indexing at [0] not at [1]. To call the elements in a list with 3 values use: lst[0], lst[1], lst[2].

5.5.2. Slicing Lists

Colons : are used inside the square brackets to denote all

>>> lst = [2, 4, 6]
>>> lst[:]
[2, 4, 6]

Negative numbers can be used as indexes to call the last number of elements in the list

>>> lst = [2, 4, 6]
>>> lst[-1]
6

The colon operator can also be used to denote all up to and thru end.

>>> lst = [2, 4, 6]
>>> lst[:2]         # all up to 2
[2, 4]

>>> lst = [2, 4, 6]
>>> lst[2:]         # 2 thru end
[6]

The colon operator can also be used to denote start : end + 1. Note that indexing here in not inclusive. lst[1:3] returns the 2nd element, and 3rd element but not the fourth even though 3 is used in the index.

Remember! Python indexing is not inclusive. The last element called in an index will not be returned.