Position of the left nearest one value in a vector

I have a vector of ones and zeros of this form: v = [0 0 1 0 0 0 1 1 1 1 0 0 1 1 0 0 0 0 0 1 0];

how can I get a vector with the left nearest zero from the one values, so that the output x is:

v = [0 0 1 0 0 0 1 1 1 1 0 0 1 1 1 0 0 1 0];

x = [0 0 2 0 0 0 6 6 6 6 0 0 12 12 12 0 0 17 0];

I am shamelly blocked so any hint to at least how to begin with would be very much appreciated.

Answer 1

[madhan ravi]

I don't know what you mean by shamely blocked.

It's not a trivial one though.

x=v;
Start=strfind([0,v==1],[0,1]);
End=strfind([v==1,0],[1,0]);
x(v==1)=repelem(Start-1,diff([Start;End+1]))

Answer 2

[Bruno Luong]

v = [0 0 1 0 0 0 1 1 1 1 0 0 1 1 1 0 0 1 0] % requirement: it must start with 0

Method 1

i0=find(v==0);
i1=find(v==1);
[~,loc]=histc(i1, [i0 Inf]);
v(i1)=i0(loc)

Method 2 (work with recent MATLAB versions)

i0=find(v==0);
i1=find(v==1);
v(i1)=interp1(i0,i0,i1,'previous')

Answer 3

[Stephen23]

>> v = [0,0,1,0,0,0,1,1,1,1,0,0,1,1,1,0,0,1,0]
v =
     0     0     1     0     0     0     1     1     1     1     0     0     1     1     1     0     0     1     0
>> d = diff([v,0])>0;
>> f = [0,find(d)];
>> x = f(1+v.*cumsum(d))
x =
     0     0     2     0     0     0     6     6     6     6     0     0    12    12    12     0     0    17     0