Arrays in Python

One-Dimensional Array Data Structure

• Linear data structures consist of a sequence of data elements of the same type.
• Array elements are accessed via an index, which is used to access and modify values.
• Python represents one-dimensional array data structures with the "list" data type, providing easy element access by index or range.
• The in operator and for...in command support iteration over array elements.

Calculating the Average Value of a Sequence

• The code to calculate the average value of a number sequence is: mean = sum(A)/len(A).

Traversing an Array in Reverse

• Method 1 involves using a for loop with a range function to iterate backward through the array.
• Method 2 entails using extended slicing to reverse the array and then iterating through it.

Two-Dimensional Array Data Structure

• In Python, two-dimensional array data structures are supported using lists.
• Each element of a list can be another list.
• A list of student names and scores might be represented as DS_diem = [["Quang", 7.5], ["Ha", 8.0], ["Binh", 9.5]].
• To iterate through and print student names and scores, you can use a for loop.

Inputting HS Data and Calculating Averages (Method 1)

• Iterating through data to input HS names and scores with a for loop, then printing names (ds[0]) and scores (ds[1]).

Inputting HS Data and Calculating Averages (Method 2)

• To input HS names and scores, use a for loop, then print the HS and their scores.

Program to Input HS Data from Keyboard

• The program calculates the average score after inputting HS names and three scores from the keyboard.

Statements About Array Type

• An appropriate statement about a one-dimensional array is that it is a finite sequence of the same data type.

Factors in Building and Using a One-Dimensional Array

• The correct approach to building and using a one-dimensional array is to consider the element addressing method.

Identifying a One-Dimensional Array

• An example of one-dimensional array data is ["One", "Two", "Three"].

Matrix Representation in Python

• For a matrix A of size m × n represented as a list of lists, the list A has m elements.

Declaring an Array of Real Numbers

• To declare an array 'a' consisting of 10 real number elements, appropriate syntax would be: a=[10] of float;.

Calculating Average Height

• To calculate the average height of students in a class, the command is: heightTB = sum(A)/len(A).

Matrix Input Program

• The program inputs an m x n matrix from the keyboard.

Unit Matrix Function

• UnitMatrix(n) can be written in multiple ways.
• Using loops and temporary lists, it constructs an identity matrix.

Finding Two Sequences

• The goal is to identify two sequences, B and C, from an initial sequence A.
• Sequence B contains the distinct elements of A, and sequence C contains the frequency of each corresponding number in B.
• After identifying B and C, you can quickly establish the program's output.
• The sequences B and C are calculated using the tinh_lap(A) function.

Electric Bill Information Array

• Assume an information array for electricity bills forms an n x 12 matrix.
• Given matrix A containing the electric bill, the program below calculates an array B of n numbers.
• Each element represents the average electricity consumption for the year corresponding to each row of matrix A.