Manipulation and pattern recognition within a matrix. With six different examples.

matrix_experiments.py

# S. No, Student Name, Science, English, History, Arts, Maths
classroom = [ [1, 'Roy', 80, 75, 85, 90, 95], 
[2, 'John', 75, 80, 75, 85, 100],
[3, 'Dave', 80, 80, 80, 90, 95]]

print('[OUT] E.g. 0')
print(classroom)
print('Pretty print: ' + '\n' + '---------')
for student in classroom:
    # print(len(student))
    print('Name: ' + student[1] + 
    '\n' + 'Science: ' + str(student[2]) + 
    '\n')

print('\n' + '------' + '\n')
# Each element in 1st dimension is a row
# Each element in the 2nd dimension is a column
# If each row has the same no. of columns, only then it is a matrix...
# ...otherwise it's a nested list.

# E.g. 1: Initialise a 6x6 matrix with the value 0.
print('[OUT] E.g. 1')
# create 6 columns
eg1_matrix = [0] * 6
print(eg1_matrix)
print('Length: ' + str(len(eg1_matrix)))
for row in range(6):
    eg1_matrix[row] = [0] * 6
print(eg1_matrix)
print('Length: ' + str(len(eg1_matrix)))
print('\n' + '------' + '\n')

# E.g. 2: Decrementing a list
print('[OUT] E.g. 2')
eg2_lst = [1,2,3,4,5]
eg2_lstLen = len(eg2_lst)
for revPtr in range(eg2_lstLen, -1, -1): 
    print(revPtr)

print('\n' + '------' + '\n')

# E.g. 3: Incrementing a list by alternate elements
print('[OUT] E.g. 3')
eg3_elements = ['a', 'b', 'c', 'd']
for element in range(len(eg3_elements)):
    if (element % 2) == 0:
        print('Even index: ' + str(element) + ', value: ' + str(eg3_elements[element]))
    if (element % 2) == 1:
        print('Odd index: ' + str(element) + ', value: ' + str(eg3_elements[element]))

print('\n' + '------' + '\n')

# E.g. 4: Iterating a matrix
print('[OUT] E.g. 4')
eg4_matrix = [
    ['a', 'b', 'c', 'd'],
    ['e', 'f', 'g', 'h'],
    ['i', 'j', 'k', 'l']
]
width = len(eg4_matrix[0]) # x
height = len(eg4_matrix) # y
print('width: ' + str(width))
print('height: ' + str(height))

for y in range(height-1):
    # print('y: ' + str(eg4_matrix[y]))
    for x in range(width-1):
        print(eg4_matrix[y][x])

print('\n' + '------' + '\n')

# E.g. 5: Picking out sublists from a row
print('[OUT] E.g. 5')
eg5_matrix = [
    ['a', 'b', 'c', 'd'],
    ['e', 'f', 'g', 'h'],
    ['i', 'j', 'k', 'l']
]
upTo = 3
width = len(eg4_matrix[0]) # x
height = len(eg4_matrix) # y
print('width: ' + str(width))
print('height: ' + str(height))

for y in range(height):
    a = eg5_matrix[y]
    for startSlice in range(len(a)):
        endSlice = upTo-1
        aSublist = a[startSlice:endSlice]
        aSet = set(aSublist)
        if len(aSet) == 1:
            pass
            # Match found
            # print('len(aSet)/match: ' + str(len(aSet)))
            # exit()
        else:
            pass
            # print('len(aSet): ' + str(len(aSet)))
        endSlice += 1

print('\n' + '------' + '\n')

# E.g. 6: 3-in-a-row checker
print('[OUT] E.g. 6')
eg6_matrix = [
    [2, 1, 1],
    [2, 1, 1],
    [1, 2, 2]
]
# Flag tracking if a 3-in-a-row was found in the board
finished = False

# Methods for checking 3-in-a-row

# Check horizontally
def horizontalCheck(row, col):
    threeInARow = False
    consecutiveCount = 0

    # From starting position to end of row...
    for j in range(col, 3):
        if eg6_matrix[row][col] == eg6_matrix[row][j]:
            consecutiveCount += 1
        else:
            break
        if consecutiveCount >= 3:
            threeInARow = True
            if eg6_matrix[row][col] == 1:
                print('p1 wins on horizontal, row: ' + str(row+1))
            elif eg6_matrix[row][col] == 2:
                print('p2 wins on horizontal, row: ' + str(row+1))
            return threeInARow

# Check vertically
def verticalCheck(row, col):
    threeInARow = False
    consecutiveCount = 0

    for i in range(row, 3):
        if eg6_matrix[row][col] == eg6_matrix[i][col]:
            consecutiveCount += 1
        else:
            break
        if consecutiveCount >= 3:
            threeInARow = True
            if eg6_matrix[row][col] == 1:
                print('p1 wins on vertical, col: ' + str(col+1))
            elif eg6_matrix[row][col] == 2:
                print('p2 wins on vertical, col: ' + str(col+1))
            return threeInARow

# Check diagonally
def diagonalCheck(row, col):
    print('row: ' + str(row) + ', col: ' + str(col))
    threeInARow = False
    count = 0
    slope = None

    consecutiveCount = 0
    j = col
    print('scanning positive slope...')
    for i in range(row, 3):
        print('i: ' + str(i) + ', j: ' + str(j))
        if j >= 3:
            break
        elif eg6_matrix[row][col] == eg6_matrix[i][j]:
            consecutiveCount += 1
        else:
            break
        # Move along 1 col, 1 row to essentially move 1 down diagonally
        j += 1

    if consecutiveCount >= 3:
        count += 1 
        slope = 'positive'
        if eg6_matrix[row][col] == 1:
            print('p1 wins on diagonal, slope: ' + slope)
        elif eg6_matrix[row][col] == 2:
            print('p2 wins on diagonal, slope: ' + slope)
    
    consecutiveCount = 0
    j = col
    print('scanning negative slope...')
    for i in range(row, -1, -1):
        if j >= 3:
            break
        elif eg6_matrix[row][col] == eg6_matrix[i][j]:
            consecutiveCount += 1
        else:
            break
        # Move along 1 col, -1 row to essentially move 1 up diagonally
        j += 1

    if consecutiveCount >= 3:
        count += 1
        slope = 'negative'
        if eg6_matrix[row][col] == 1:
            print('p1 wins on diagonal!')
        elif eg6_matrix[row][col] == 2:
            print('p2 wins on diagonal!')
    
    if count > 0:
        print('count (>): ' + str(count))
        threeInARow = True
    if count == 2:
        print('count (==): ' + str(count))
        slope = 'both'
    return threeInARow, slope


# Check if there's a 3-in-a-row in the board
def checkForFours():
    # For each counter in the board...
    for i in range(columnLength): # col elems
        for j in range(rowLength): # row elems
            # We only check for 3-in-a-row starting at (i,j)
            if eg6_matrix[i][j] != 0:
                if horizontalCheck(i, j):
                    finished = True
                    print('horizontal match!')
                    break
                if verticalCheck(i, j):
                    finished = True
                    print('vertical match!')
                    break
                diag_threes, slope = diagonalCheck(i, j)
                if diag_threes:
                    print('checkForFours/slope: ' + slope)
                    finished = True
                    break

# Find out dimensions of board
columnLength = len(eg6_matrix)
rowLength = len(eg6_matrix[0])
print('columnLength: ' + str(columnLength))
print('rowLength: ' + str(rowLength))

checkForFours()

print('\n' + '------' + '\n')