Question

从鼠标单击的位置为2d数组创建索引时遇到问题。该程序应该通过检查鼠标单击相对于数组中每个正方形（正方形）的正方形（只有1d）来工作。正方形是来自称为正方形的类的对象的数组，该对象绘制在屏幕上。 2d数组是由1和0组成的数组，会随机生成为用户输入的大小。

仅当鼠标单击位置在正方形内时，才应创建新索引，并且仅生成该正方形的索引。

for n in range(len(squares)):
    for square in squares:
        if square.x < x < (square.x+17) and square.y < y < (square.y+17):
            j = int(n/width)
            i = n - j*width
            print(j,i)

但是该程序为1d数组中的每个正方形生成2d数组索引，而不只是鼠标单击所在的正方形。

那么我如何使此代码按预期工作？

Answer 1

似乎您只需要删除嵌套循环并使用索引n即可访问当前正方形：

for n in range(len(squares)):
    square = squares[n]
    if square.x < x < (square.x+17) and square.y < y < (square.y+17):
        j = int(n/width)
        i = n - j*width
        print(j,i)

同时遍历索引和项目的惯用方式是enumerate列表：

for n, square in enumerate(squares):
    if square.x < x < (square.x+17) and square.y < y < (square.y+17):

如果要处理网格，则还可以将鼠标坐标除以tileize大小，以得到索引。然后以这种方式将2D索引转换为1D索引：i = x + width*y。这意味着您不必再遍历正方形即可检查碰撞。

下面是一个示例，其中包含pygame.Rect的列表和颜色，您可以通过单击单元格来更改它们：

import pygame as pg


pg.init()
screen = pg.display.set_mode((640, 480))
clock = pg.time.Clock()
BG_COLOR = pg.Color('gray12')
ORANGE = pg.Color(200, 100, 0)
BLUE = pg.Color('dodgerblue1')

tilesize = 27
width = 16
height = 10
# A list of pygame.Rects + colors.
squares = [[pg.Rect(x*tilesize, y*tilesize, tilesize-1, tilesize-1), ORANGE]
           for y in range(height) for x in range(width)]

done = False
while not done:
    for event in pg.event.get():
        if event.type == pg.QUIT:
            done = True
        elif event.type == pg.MOUSEBUTTONDOWN:
            # Floor division by the tilesize to get the x and y indices.
            x, y = event.pos[0]//tilesize, event.pos[1]//tilesize
            if 0 <= x < width and 0 <= y < height:  # Inside of the grid area.
                i = x + width*y  # Index of the 1D list.
                print(x, y, i)
                # I just toggle the color here.
                squares[i][1] = BLUE if squares[i][1] == ORANGE else ORANGE

    screen.fill(BG_COLOR)
    for square, color in squares:
        pg.draw.rect(screen, color, square)
    pg.display.flip()
    clock.tick(60)

pg.quit()

如何将一维数组的索引转换为二维数组？

1 个答案: