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How can I convert the grid of symbols into a list of strings

Time:12-31

the input for the to_strings function is the grid so whatever that the grid shows should be converted into a list of strings where input example :

   A B C
 1 . . .
 2 . @ .
 3 . O .

output example :

['...', '.@.', '.O.']
True

first Issue is in this particular function as it does not provide the expected output

    def to_strings(self):
        from itertools import chain

        m_list_tostring=[]
        for i in range(len(self.grid)):
            x=list(chain.from_iterable(self.grid))
            m_list_tostring = ''.join([str(x) for self.grid, i in enumerate(x)])  # to convert the list of characters into a string
        print(x)

    return str(x)

I also have an issue with a particular assertion error that needs to be raised where it checks for invalid inputs (the letter x should indicate the row coordinate of the invalid row) where "invalid character in row x" the code shown below is what i came up with however it gives an error

assert i == self.grid[i], "invalid character in row " i

I need to add an additional optional argument from_strings to the constructor. If it's present, this argument must be a list of strings where each string gives a row of the board with the character encoding used in the __str__() method, but without the spaces and the coordinate letters.

And also a method to_strings(self) that gives a representation of the board as a list of strings in the same format as that accepted by the __init__() method from the from_strings.

How can i get the expected output ?

from string import ascii_uppercase as letters
class Board:
#Dictionary created for the colours and the respected symbols
    points = {'E': '.', 'B': '@', 'W': 'O'}
#Constructor
    def __init__(self,size=19,from_strings=None):
        assert 2 <= size <= 26, "Illegal board size: must be between 2 and 26."
        assert type(from_strings) is list,"input is not a list"
        assert len(from_strings)==size, "length of input list does not match size"
        for i in from_strings:
            assert type(i)==str, "row " i " is not a string"
            assert len(i)==size,"length of row " i " does not match size"
            #assert i== b[i], "invalid character in row " i
        self.size = size
        self.grid = [['E'] * size for _ in range(size)]
        self.from_strings = [] if from_strings is None else from_strings
       def get_size(self): #Returns the size of the grid created by the constructor
        return self.size

    def __str__(self): #creating the grid
        padding=' ' #Creating a variable with a space assigned so that it acts as a padding to the rows that have a single digit
        heading = '   '   ' '.join(letters[:self.size]) #Alphabetical heading is created
        lines = [heading] #adding the alphabetical heading into a list named lines to which the rows will be added later
        for r, row in enumerate(self.grid):
            if len(self.grid)<10: #for the grid with a size less than 10 to add the space to the start of the row for the single digits to be aligned
                line = " "  f'{self.size - r} '   ' '.join(self.points[x] for x in row)
                lines.append(line)
            else: #for the grids that are larger than 9
                if r>9: #for rows 1 to 9 the single digits are aligned according to the first digit from the right of the two digit rows
                    line =f'{self.size - r} '   ' '.join(self.points[x] for x in row)
                    line=padding line #adding the space using the variable padding to the row created
                    lines.append(line) #adding the row to the list of rows
                else: #for the rows 10 onwards - as there is no requirement to add a padding it is not added here
                    line = f'{self.size - r} '   ' '.join(self.points[x] for x in row)#creation of the row
                    lines.append(line) #adding the newly created row to the list of rows
        return '\n'.join(lines)


    def _to_row_and_column(self, coords):
        # destructure coordinates like "B2" to "B" and 2
        alpha, num = coords
        colnum = ord(alpha) - ord('A')   1
        rownum = self.size - int(num)   1
        assert 1 <= rownum <= self.size,"row out of range"
        assert 1 <= colnum <= self.size,'column out of range'
        return rownum, colnum

    def set_colour(self, coords, colour_name):
        rownum, colnum = self._to_row_and_column(coords)
        assert len(coords)==2 or len(coords)==3, "invalid coordinates"
        assert colour_name in self.points,"invalid colour name"
        self.grid[rownum - 1][colnum - 1] = colour_name

    def get_colour(self, coords):
        rownum, colnum = self._to_row_and_column(coords)
        return self.grid[rownum - 1][colnum - 1]

    def to_strings(self):
        from itertools import chain
        m_list_tostring=[]
        for i in range(len(self.grid)):
            x=list(chain.from_iterable(self.grid))
            m_list_tostring = ''.join([str(x) for self.grid, i in enumerate(x)])  # to convert the list of characters into a string
            print(x)
        
        return x

b =Board(3, ["O.O", ".@.", "@O."])
print(b)
print(b.to_strings())
c =Board(b.get_size(), b.to_strings())
print(str(b) == str(c))

for now my code is as such

however I'm not getting the expected output which is shown below

   A B C
 3 O . O
 2 . @ .
 1 @ O .

['O.O', '.@.', '@O.']
True

so the output i got is from my code is :

['E', 'E', 'E', 'E', 'E', 'E', 'E', 'W', 'E']

CodePudding user response:

I executed the code myself and make some changes to get closer to your desired answer.

First ,i don't know exactly what this line do , neither what b stands for , so i removed it:

assert i== b[i], "invalid character in row " i.

Then i looked to _str_ method, that is the method that do the class printing, when you call:

print(b)

It doesn't have any mentions to self.from_strings

Basically in each line , respecting formatting style for the size the of the grid, it is print the correspondent character of the letter you defined in points dictionary as we can see here :

join(self.points[x] for x in row)

Since the points and grid is like this :

self.grid = [['E'] * size for _ in range(size)]

points = {'E': '.', 'B': '@', 'W': 'O'}

It gives the output:

   A B C
 3 . . .
 2 . . .
 1 . . .

Assuming that you when from_strings parameter you want that class print that way , i used conditional to use this

    def __str__(self): #creating the grid
            padding=' ' #Creating a variable with a space assigned so that it acts as a padding to the rows that have a single digit
            heading = '   '   ' '.join(letters[:self.size]) #Alphabetical heading is created
            lines = [heading] #adding the alphabetical heading into a list named lines to which the rows will be added later
            for r, row in enumerate(self.grid):
                if len(self.grid)<10: #for the grid with a size less than 10 to add the space to the start of the row for the single digits to be aligned
                    if (self.from_strings):
                        line = " "  f'{self.size - r} '   ' '.join(self.from_strings[r])
                    else: 
                        line = " "  f'{self.size - r} '   ' '.join(self.points[x] for x in row)
                    lines.append(line)
                else: #for the grids that are larger than 9
                    if r>9: #for rows 1 to 9 the single digits are aligned according to the first digit from the right of the two digit rows
                        if (self.from_strings):
                            line = f'{self.size - r} '   ' '.join(self.from_strings[r])
                        else:
                            line =f'{self.size - r} '   ' '.join(self.points[x] for x in row)
                        line=padding line #adding the space using the variable padding to the row created
                        lines.append(line) #adding the row to the list of rows
                    else: #for the rows 10 onwards - as there is no requirement to add a padding it is not added here
                        if (self.from_strings):
                            line = f'{self.size - r} '   ' '.join(self.from_strings[r])
                        else: 
                            line = f'{self.size - r} '   ' '.join(self.points[x] for x in row)#creation of the row
                        lines.append(line) #adding the newly created row to the list of rows
            return '\n'.join(lines)

And use the same logic to to_strings method :

    def to_strings(self):
        padding=' '
        lines = [] 
        for r, row in enumerate(self.grid):
            if self.from_strings : 
                lines.append(''.join(self.from_strings[r]))
            else :
                lines.append(''.join(self.points[x] for x in row))
        return lines

The output is shown like this :

   A B C
 3 O . O
 2 . @ .
 1 @ O .
['O.O', '.@.', '@O.']
True
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