How to extract the scatter data based on a function

1 次查看（过去 30 天）

joynjo 2018-7-18

0
链接

此问题的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/410826-how-to-extract-the-scatter-data-based-on-a-function

编辑： joynjo 2018-7-21

I have a scatter data as attached image follows, how to sign the data outside the function line with '1' and the data under the function line with '0' then save it into one variable?

1 个评论
显示 -1更早的评论隐藏 -1更早的评论

joynjo 2018-7-21

Up, I am still waiting for anyone who can help me solve this problem, thanks

请先登录，再进行评论。

请先登录，再回答此问题。

回答（1 个）

Image Analyst 2018-7-18

0
链接

此回答的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/410826-how-to-extract-the-scatter-data-based-on-a-function#answer_329220

在 MATLAB Online 中打开

I have no idea what "sign the data" with 0 or 1 means, but to get the data under and above/outside the function, try something like this

indexesUnderTheCurve = false(1, length(x));
for k = 1 : length(x)
  thisX = x(k);
  thisY = y(k);
  curveY = YourFunction(thisX); % Plug the x into your custom function
  if thisY < curveY
    % Under the curve
    indexesUnderTheCurve(k) = true;
  end
end
xUnder = x(indexesUnderTheCurve);
yUnder = y(indexesUnderTheCurve);
xOver = x(~indexesUnderTheCurve);
yOver = y(~indexesUnderTheCurve);