(B17) Python part5 Python Data Type - Collection(Arrays) 1- List , Tuple, Set, Dictionary

20220520 152734
Python Collections (Arrays)
There are four collection data types in the Python programming language:

List is a collection which is ordered and changeable. Allows duplicate members.

Tuple is a collection which is ordered and unchangeable. Allows duplicate members.

Set is a collection which is unordered, unchangeable*, and unindexed. No duplicate members.

Dictionary is a collection which is ordered** and changeable. No duplicate members.

*Set items are unchangeable, but you can remove and/or add items whenever you like.

----------------------------------------------
List:[]
Lists are used to store multiple items in a single variable.
Lists are one of 4 built-in data types in Python used to store collections of data, the other 3 are Tuple, Set, and Dictionary, all with different qualities and usage.

Lists are created using square brackets:

EX.
thislist = ["apple", "banana", "cherry"]

print(thislist)

List Items
List items are ordered, changeable, and allow duplicate values.

List items are indexed, the first item has index [0], the second item has index [1] etc.

A = [23,45,72,23,88,44,72,98]
print(A)
[23, 45, 72, 23, 88, 44, 72, 98]
print(type(A))
class 'list'
print(len(A))
8

index:
-8 -7 -6 -5 -4 -3 -2 -1
[23,45,72,23,88,44,72,98]
0 1 2 3 4 5 6 7

A[0]
23
A[1]
45
A[6]
72
A[3:]
[23, 88, 44, 72, 98]
A[2:5]
[72, 23, 88]
A[-6]
72
A[-6:-3]
[72, 23, 88]

A
[23, 45, 72, 23, 88, 44, 72, 98]
A.extend([33,44,55])
A
[23, 45, 72, 23, 88, 44, 72, 98, 33, 44, 55]
A[8]
33
A[9]
44

A
[23, 45, 72, 23, 88, 44, 72, 98, 33, 44, 55]
A.append([12,13,14])
A
[23, 45, 72, 23, 88, 44, 72, 98, 33, 44, 55, [12, 13, 14]]
A[-1]
[12, 13, 14]
A.pop()
[12, 13, 14]
A
[23, 45, 72, 23, 88, 44, 72, 98, 33, 44, 55]
A.pop()
55
A
[23, 45, 72, 23, 88, 44, 72, 98, 33, 44]

A
[23, 45, 72, 23, 88, 44, 72, 98, 33, 44]

A.index(88)
4
A.index(98)
7

A.count(72)
2
A.count(44)
2
A.count(88)
1

A
[23, 45, 72, 23, 88, 44, 72, 98, 33, 44]
A.sort()
A
[23, 23, 33, 44, 44, 45, 72, 72, 88, 98]
A.reverse()
A
[98, 88, 72, 72, 45, 44, 44, 33, 23, 23]

A.remove(33)
A
[98, 88, 72, 72, 45, 44, 44, 23, 23]
A.remove(44)
A
[98, 88, 72, 72, 45, 44, 23, 23]

A.insert(3,79)
A
[98, 88, 72, 79, 72, 45, 44, 23, 23]
A[1]
88
A[1]=28
A
[98, 28, 72, 79, 72, 45, 44, 23, 23]

A
[98, 28, 72, 79, 72, 45, 44, 23, 23]
A * 2
[98, 28, 72, 79, 72, 45, 44, 23, 23, 98, 28, 72, 79, 72, 45, 44, 23, 23]
B = [101, 204, 509, 309]
A + B
[98, 28, 72, 79, 72, 45, 44, 23, 23, 101, 204, 509, 309]
---------------------------------------------------------------
Tuple: ()
Tuples are used to store multiple items in a single variable.

Tuple is one of 4 built-in data types in Python used to store collections of data, the other 3 are List, Set, and Dictionary, all with different qualities and usage.

A tuple is a collection which is ordered and unchangeable.

Tuples are written with round brackets.

Ex.

thistuple = ("apple", "banana", "cherry")
print(thistuple)

Tuple Items
Tuple items are ordered, unchangeable, and allow duplicate values.

Tuple items are indexed, the first item has index [0], the second item has index [1] etc.

-----------
C = (12,44,82,46,19,52,61,34)
print(C)
(12, 44, 82, 46, 19, 52, 61, 34)
print(type(C))
class 'tuple'
len(C)
8

-8 -7 -6 -5 -4 -3 -2 -1
(12,44,82,46,19,52,61,34)
0 1 2 3 4 5 6 7

C.index(46)
3

C.count(44)
1
C[0]
12
C[4]
19
C[4:]
(19, 52, 61, 34)
C[3:6]
(46, 19, 52)

C[1]
44
C[1]=55
Traceback (most recent call last):

C[1]=55
TypeError: 'tuple' object does not support item assignment

D=(55,66,12,55,78,99,12,55)

D
(55, 66, 12, 55, 78, 99, 12, 55)
D.count(55)
3
D.index(12)
2
C+D
(12, 44, 82, 46, 19, 52, 61, 34, 55, 66, 12, 55, 78, 99, 12, 55)
C * 2
(12, 44, 82, 46, 19, 52, 61, 34, 12, 44, 82, 46, 19, 52, 61, 34)

A+C
Traceback (most recent call last):

A+C
TypeError: can only concatenate list (not "tuple") to list
A *C
Traceback (most recent call last):

A *C
TypeError: can't multiply sequence by non-int of type 'tuple'
------------------------------------------------