#Matlab return index of nonzero elements how to#
#Matlab return index of nonzero elements trial#

#Matlab return index of nonzero elements how to#

I am sure this is a relatively simple thing to do so I was hoping someone could offer insight.ĮDIT: Here's what I tried: s = zeros(size(x1)) įor a vector x1 which has a max chain of 72 but I dont know how to find the max chain and return its first value, so I know where to trim. I need to get rid of these rows before I can start analyzing the movement from the trials. colind length size2()+1, which contains the index to the first non-zero element on or after the corresponding column.

#Matlab return index of nonzero elements trial#

I am working with movement data from a joystick and there are a few thousand rows of data with a mix of zeros and nonzero values before the actual trial begins (coming from subjects slightly moving the joystick before the trial actually started). Thus, the find method has a running time dictated by the overhead of copying the array and calling find, whereas the loop method time is dictated by how many array elements one needs to visit to find the first non-zero element.I am trying to write a simple MATLAB program that will find the first chain (more than 70) of consecutive nonzero values and return the starting value of that consecutive chain. Another method for accessing elements of an array is to use only a single index, regardless of the size or dimensions of the array. Based on your location, we recommend that you select. I would like the information to appear like this: (row number,column numer). Choose a web site to get translated content where available and see local events and offers.

q is the location of the first non-zero element. at 1:49 s zeros (size (x1)) for i2:length (x1) if (x1 (i-1)0) s (i) 1 + s (i-1) end end display (S) for a vector x1 which has a max chain of 72 but I dont know how to find the max chain and return its first value, so i know where to trim. Lets say I have a 100x10 cell array of 0 and 1 (false and true).

Test results depend, of course, on the expected number of elements to visit before a non-zero element is found, as well as on the array length n. i,j,v find (X) returns a column vector v of the nonzero entries in X. i,j find (X) returns the row and column indices of the nonzero entries in the matrix X. Sometimes it is useful to simultaneously change the values of several existing array elements. If none is found, find returns an empty matrix. function to get the index of the element equal to 8 that satisfies the conditions. 3 1 output r is 4 Solution BE MATLAB Documentation function r fullest row (a). (I didn't add the bwconncomp answer because it's significantly slower). k find (X) returns the indices of the array X that point to nonzero elements. Most nonzero elements in row Given the matrix a, return the index r of the. floor(r)) /2 The column number can be found by subtracting current linear index from the linear index of the first element of the current row and adding R to it. Method2 is the fixed version of this answer, using find and copying the array. For the column number we find the index of the first element idxfirst of the current row R: idxfirst(floor(r+1).