Code

from random import randint

map_content = [ #each dict will be called 'tile_dict'
    {'type': 'Stone', 'symbol': "[]"},
    {'type': 'Air', 'symbol': "O"},
    {'type': 'Grass', 'symbol': "_"},
    {'type': 'Dirt', 'symbol': "*", 'generation': [(2,2),(3,2),(2,3),(4,4),(2,1),(2,2)],'rarity': 50},
    {'type': 'Coal', 'symbol':  "5", 'generation': [(1,0),(0,1),(1,1),(1,2),(2,1),(2,2)],'rarity': 10},
    {'type': 'Iron', 'symbol': "Fe", 'generation': [(0,0),(1,0),(0,1),(1,1),(1,2),(2,1)],'rarity': 30}
]
#generatables=['Dirt','Coal','Iron'] # in ascending order of rarity

game_map=[]
map_x = 101
map_y = 101
for y in range(0,map_y): #makes a blank map
    x_layer = []
    for x in range(0,map_x):
        x_layer.append('')
    game_map.append(x_layer)

# for x in map:
#     print(x)

#convinience functions
def get_index(x,y):
    x_index = (((map_x/2).__ceil__())-1)+x
    y_index = (y*-1)+((map_y/2).__ceil__())-1
    return (y_index,x_index)

def get_cords(x_index,y_index):
    x = x_index-(((map_x/2).__ceil__())-1)
    y = ((y_index+1)-(map_y/2).__ceil__())*-1
    return (x,y)

def get_from_map_content(key,key_target,dict): ## not sure about func name
    for tile_dict in dict:
        if tile_dict[key] == key_target: # stopped here
            return tile_dict

def get_tile_from_map(pos): # receives cords
    x = pos[0]
    y = pos[1]
    index = get_index(x,y)
    tile = game_map[index[0]][index[1]]
    tile_dict = get_from_map_content('symbol',tile,map_content)

    return (tile,tile_dict)
#=========================================================================================================================#

#Map gen functions

# fill = what type of till will be filled in that tile
def fill_map(point1,point2,content='Air'): #works like minecraft fill command only receives index
    #in content you have to input the type
    max_x = max(point1[1],point2[1])
    min_x = min(point1[1],point2[1])
    max_y = max(point1[0],point2[0])
    min_y = min(point1[0],point2[0])

    fill = get_from_map_content('type',content,map_content)

    fill_symbol = fill['symbol']
    fill_type = fill['type']

    for layer_index, layer  in enumerate(game_map):
        for collumn_index, tile in enumerate(layer):
            if min_y <= layer_index <= max_y and min_x <= collumn_index <= max_x:
                game_map[layer_index][collumn_index] = fill_symbol

def generate(start_point,fill): #fill is tile type
    tile_dict = get_from_map_content('type',fill,map_content)
    tile_generation = tile_dict['generation']
    size = tile_generation[randint(0,len(tile_generation)-1)]
    end_point = (start_point[0]+size[0], start_point[1]+size[1])

    fill_map(start_point,end_point,fill)

def generate_template():
    fill_map((0, 0), (map_y - 1, map_y - 1), 'Stone')

    for layer_index, layer in enumerate(game_map):
        for collumn_index, tile in enumerate(layer):
            if tile == '[]':
                tile_index = (layer_index, collumn_index)

                def get_rarity(tile_type):
                    rarity = get_from_map_content('type', tile_type, map_content)['rarity']
                    return rarity

                def seq_wrapper(tile_type):
                    if randint(0, get_rarity(tile_type)) == 0:
                        generate(tile_index, tile_type)
                    return tile_type

                generatables = ['Dirt', 'Coal', 'Iron']

                result = list(map(seq_wrapper, generatables))


generate_template()
surface_y = get_cords(0,1)[1]
print(surface_y)
fill_map(get_index(0,0),get_index(0,0),'Stone')
print('==================================================================')
for x in game_map:
    print(x)

print(get_tile_from_map((-5,-5),))