python带有行和列的二维数组

Question

Create a two-dimensional array named A with ROWS rows and COLS columns. ROWS and COLSS are specified by the user at run time. Fill A with randomly-chosen integers from the range [ -10,99 ], then repeatedly perform the following steps until end-of-file(1) input an integer x(2) search for x in A(3) when x is found in A, output the coordinate (row,col) where x is found, otherwise output the message "x not found!"

I need help I am wondering how can we define two-dimensional array named A with ROWS rows and COLS columns. ROWS and COLSS are specified by the user at runtime in python latest version

#--------------------------------------

#Hw 7
#E80
#---------------------------------------
A = [[Rows],[ColSS]] #I really dont know how to defend this part

for i in range (-10,99): #dont worry about this its just the logic not the actual code
x = int(input("Enter a number : "))
if x is found in A
coordinate row and clumn
otherwise output "x is not found"

Answer 1

The idiomatic way to create a 2D array in Python is:

rows,cols = 5,10
A = [[0]*cols for _ in range(rows)]

Explanation:

>>> A = [0] * 5  # Multiplication on a list creates a new list with duplicated entries.
>>> A
[0, 0, 0, 0, 0]
>>> A = [[0] * 5 for _ in range(2)] # Create multiple lists, in a list, using a comprehension.
>>> A
[[0, 0, 0, 0, 0], [0, 0, 0, 0, 0]]
>>> A[0][0] = 1
>>> A
[[1, 0, 0, 0, 0], [0, 0, 0, 0, 0]]

Note you do not want to create duplicate lists of lists. It duplicates the list references so you have multiple references to the same list :

>>> A = [[0] * 5] * 2
>>> A
[[0, 0, 0, 0, 0], [0, 0, 0, 0, 0]]
>>> A[0][0] = 1
>>> A
[[1, 0, 0, 0, 0], [1, 0, 0, 0, 0]]  # both rows changed!