Matlab:如何找到范围？

Question

我有一个1s和0的二进制向量。我想找一个数字1的函数范围/岛。例如:X=00011110011111000110.我需要一个这样的答案: 4-7 (或45-67)，10-16，20-21 .谢谢你的帮助！

Answer 1

Aki解决方案的变体(测试不多)：

x = [0 0 0 1 1 1 1 0 0 1 1 1 1 1 1 1 0 0 0 1 1 0];
dx = diff([0, x, 0]);
start_pos = find(dx == 1);
end_pos = find(dx == -1) - 1;

Answer 2

向原始数组的两端添加零可以保证转换的偶数(从0开始到1开始，结尾从1到0)。这基本上是一个diff和细化输出的问题。

x = [0 0 0 1 1 1 1 0 0 1 1 1 1 1 1 1 0 0 0 1 1 0];
% how to make that out from a string  xx="0001111001111111000110" is left
% as an exercise
y = [0 x 0];        %  make sure x="11"; has proper amount of transitions
R = 1:length(y)-1;  %  make an array of indices [1 2 3 4 5 ... end-1]
F = R(y(2:end) != y(1:end-1));          % finds the positions [4,8,10,17,20,22]
start_pos = F(1:2:end-1);  % gets 4,10,20
end_pos = F(2:2:end)-1;    % gets 7,16,21 adjusted

免责声明:未经测试。