^^Python. Built-in compound types. list tuple range set dict

compound types ()-tuple []-list {}-dictionary

4.6. Sequence Types — list, tuple, range

4.9. Set Types — set, frozenset

class range(stop) class range(start, stop[, step])

range represents an immutable sequence of numbers ≥start <stop
commonly used for looping a specific number of times in for loops for x in y:
0 start default; 1 step default
es range(5) represent (0, 1, 2); range(5, 8) represent (5, 6, 7)
es: represent ()

range	represent
range(0, 9)	0, 1, 2, 3, 4, 5, 6, 7, 8, 9
range(1, 10)	1, 2, 3, 4, 5, 6, 7, 8, 9
range(1, 11)	1, 2, 3, 4, 5, 6, 7, 8, 9, 10
range(10, 20, 2)	10, 12, 14, 16, 18
range(5.2, 6, 0.3)	5.2, 5.5, 5.8

list(range(10))    [0, 1, 2, 3, 4, 5, 6, 7, 8, 9]

tuple(range(10))   (0, 1, 2, 3, 4, 5, 6, 7, 8, 9)

()-tuple []-list {}-dictionary

Type	Example	Bracket	Description
`list`	`[1, "two", 3.14]`	square	sequence, mutable
`tuple`	`(1, 2, 3)`	round	sequence, immutable
`range`	`range(10)`	round	sequence, immutable
`set`	`{1, 2, 3}`	curly	unordered collection of unique values
`dict`	`{'a':1, 'b':2, 'c':3}`	curly	unordered (key:value) mapping

vo: ordered collection ≡ sequence

Compound objects can contain as elements, objects of:

any type, mixed types, other compound objects.
es: lista di liste

List of dictionaries

data = [{'nome':'Roberto', 'cgn':'Occa',  'YOB':1954},
        {'nome':'Mario',   'cgn':'Occa',  'YOB':1920},
        {'nome':'Annita',  'cgn':'Gaffo', 'YOB':1912}]

Such type flexibility

is an essential piece of what makes Python code relatively quick and easy to write.
is possible by Python's dynamic type system.

Access to elements in compound types

indexing for single elements
- reverse indexing: -1 last element index
slicing for multiple elements.

Strings, String Type.

Tuple is immutable

tryng to mutate it, result in

 TypeError: 'tuple' object does not support item assignment

 AttributeError: 'tuple' object has no attribute 'append

Links

faq/Why are there separate tuple and list data types?