Please check the data to see if there is such a situation as [1 hr class= 2 answer 3 4 5 1], that is, from the origin to the origin.
in addition to the supply code, how can people judge the problem?

the problem has been solved. If a small partner has this kind of problem. You can check whether the source data is incorrect. Because I have a lot of code and miscellaneous, so I didn't post it. For example, the data used for the first drawing is x = [1, 2, 3, 4, 5, 6], y = [10, 12, 13, 11, 10, 13]; Later, I need to redraw the graph. Although I use the cla () method and query the new data x = [7, 8, 9, 10], y = [9, 11, 10, 8] and then draw the graph, because the x and y data in my code are stored with the class attributes of the object, I did not empty the original data. The data of the second drawing becomes: X = [1, 2, 3, 4, 5, 6, 7, 8, 9, 10], y = [10, 12, 13, 11, 10, 13, 9, 11, 10, 8]. As a result, the above results are produced. Not only that, but the axes also produce strange changes. I was convinced myself.