计算向量中连续的1和0的数目 [英] Count numbers of consecutive 1s and 0s in a vector

问题描述

在Matlab中，我有一个看起来像这样的向量:

In Matlab I have a vectors that looks like this:

0 0 1 1 0 0 0 1 1 0 0 0 0 1 1 1 0 0 0 0 1 0 1

我现在要做的是计算此向量中的1的数量.连续的1s计为1.此外，我还想计算1s之间的0s的平均值和中位数.因此，对于此示例:

What I want to do now is to count the number of 1 in this vector. Consecutive 1s count as 1. Additionally, I want also to calculate the average and median numbers of 0s between 1s. So for this example:

1秒:5

中位数0:3.5

平均0:3

我用蛮力方法解决了这一问题，即研究循环中的每个元素并检查上一个和下一个元素.但我敢肯定，必须有一个速度更快的解决方案.有什么主意吗?

I solved that with a brute force method, that is investigate each element in a loop and check the previous as well as the next element. But I'm sure there has to be a solution that is way faster. Any idea?

推荐答案

给出向量v，

v = [ 0 0 1 1 0 0 0 1 1 0 0 0 0 1 1 1 0 0 0 0 1 0 1 ]; % data

计算如下:

w = [ 1 v 1 ]; % auxiliary vector
runs_zeros = find(diff(w)==1)-find(diff(w)==-1); % lenghts of runs of 0's

% Desired results:
number_ones = length(runs_zeros)-1+v(1)+v(end);
% For average and median, don't count first run if v(1) is 0,
% or last run if v(end) is 0:
average_runs_zeros = mean(runs_zeros(2-v(1):end-1+v(end))); 
median_runs_zeros = median(runs_zeros(2-v(1):end-1+v(end)));

这比@TryHard的解决方案要快，因为它不需要转换为字符串

This is faster than @TryHard's solution because it doesn't require converting to strings

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