Question

我有一个如下所示的值列表：

15,100,25.0
-50,-50,50.0
-20,120,70,40
200,-100,25,5

前两行表示圆的值，第三行表示矩形，第四行表示多边形。我希望输出看起来像这样：

c 15,100,25.0
c -50,-50,50.0
r -20,120,70,40
p 200,-100,25,5

我不确定如何为每一行添加字母。我有一个for循环，我用它来浏览字符串中的信息以打印出来。

for shapes in list_of_shapes:
    print(",".join(str(item) for item in shapes))

这是我的一些代码：

list_of_shapes = []

while p >= 0:

    #Here is a bunch of code

    list_of_shapes.append("c")
    list_of_shapes.append(circle) # appends the data for the circles
while p2 >= 0:
    #bunch of code
    list_of_shapes.append("r")
    list_of_shapes.append(rect) # appends the data for the rectangle
while p3 >= 0:
    #code
    list_of_shapes.append("p")
    list_of_shapes.append(poly) # appends the data for the polygon

    return list_of_shapes

一旦我为所有人做了这件事，我最终得到了：

c
15,100,25.0
c
-50,-50,50.0
r
-20,120,70,40
p
200,-100,25,5

非常感谢任何帮助：）

Answer 1

你正在做的只是在列表中添加额外的字符串，而不是在字符串本身附加/前置。

从上面的代码中，如果你只想要一个字符串列表，你可能会这样做：

list_of_shapes = []

while p >= 0:

    #Here is a bunch of code

    list_of_shapes.append("c {0}".format(','.join(circle))) # append data for circles by converting the circle list into a string
while p2 >= 0:
    #bunch of code
    list_of_shapes.append("r {0}".format(','.join(rect))) # append data for rect by converting the rect list into a string
while p3 >= 0:
    #code
    list_of_shapes.append("p {0}".format(','.join(poly))) # append data for polygon by converting the poly list into a string

return list_of_shapes

然后你就可以像这样打印出这个列表：

for shape in list_of_shapes: print(shape)

请注意，在所有while块中，您现在只执行一次list_of_shapes.append。

这使用str.format()，它允许您以特定方式格式化字符串。

但是，如果你想单独保留所有的列表数据（而不是完全是一个字符串），那么像Snakes和Coffee建议的那样就可以了。

Answer 2

问题在于：

while p >= 0:

    #Here is a bunch of code

    list_of_shapes.append("c")
    list_of_shapes.append(circle) # appends the data for the circles
while p2 >= 0:
    #bunch of code
    list_of_shapes.append("r")
    list_of_shapes.append(rect) # appends the data for the rectangle
while p3 >= 0:
    #code
    list_of_shapes.append("p")
    list_of_shapes.append(poly) # appends the data for the polygon

    return list_of_shapes

这会给你['c', <circle>, 'r', <rect>, 'p', <poly>]。你可以这样做：

while p >= 0:

    #Here is a bunch of code
    list_of_shapes.append(("c", circle)) # appends the data for the circles
while p2 >= 0:
    #bunch of code
    list_of_shapes.append(("r", rect)) # appends the data for the rectangle
while p3 >= 0:
    #code
    list_of_shapes.append(("p", poly)) # appends the data for the polygon

    return list_of_shapes

这基本上将每个形状与其分类配对。然后你可以这样打印：

for shape_type, shape in list_of_shapes:
    print("{} {}".format(shape_type, ",".join(str(item) for item in shapes)))

Answer 3

要将您想要的信件附加到列表，您可以执行以下操作：

list = [15,100,25.0]
list_with_letter = ["c"] + list

如何在Python中向字符串添加字符串？

3 个答案: