How to count the numbers before consecutive negative values?

Hi, I have a code, whose output is:

c =
0.4855   -0.1902   -0.1758    0.3935   -0.1264   -0.1274   -0.0914   -0.1149   -0.0930    0.5572    0.5098    1.0000    
0.9737    0.9508    0.9046    0.9083    0.8997

Now, I want to calculate the maximum number of consecutive negative numbers (in this case, it is, 5) and the number of values before it (in this case, it is 4). How do I do it?

[Tawsif Mostafiz]

Thanks!

Answer 1

[Image Analyst]

Try this:

mask = bwareafilt(c < 0, 1);
props = regionprops(mask, 'Area', 'PixelIdxList')
longestRun = props.Area % Will be 5
numbersBefore = props.PixelIdxList(1) - 1 % will be 4

Answer 2

[Walter Roberson]

c = [
0.4855   -0.1902   -0.1758    0.3935   -0.1264   -0.1274   -0.0914   -0.1149   -0.0930    0.5572    0.5098    1.0000    ...
0.9737    0.9508    0.9046    0.9083    0.8997]

c = 1×17

0.4855 -0.1902 -0.1758 0.3935 -0.1264 -0.1274 -0.0914 -0.1149 -0.0930 0.5572 0.5098 1.0000 0.9737 0.9508 0.9046 0.9083 0.8997

mask = c < 0

mask = 1×17 logical array
   0   1   1   0   1   1   1   1   1   0   0   0   0   0   0   0   0

starts = strfind([0 mask], [0 1 1])

starts = 1×2

2 5

stops = strfind([mask 0], [1 1 0]) + 1

stops = 1×2

3 9

runlengths = stops - starts + 1

runlengths = 1×2

2 5

[maxrunlength, idx] = max(runlengths)

maxrunlength = 5

idx = 2

num_items_before_run = starts(idx) - 1

num_items_before_run = 4