FIND

Purpose:

Returns indices of non-zero elements or NA if none found.

Syntax:

FIND(series, first)

(row, col) = FIND(series, first)

(row, col, val) = FIND(series, first)

Returns:

A series or array.

(row, col) = FIND(series, first) returns the row and column indices of the non-zero elements.

(row, col, val) = FIND(series, first) returns the row and column indices and the non-zero elements of series.

Example:

a = {1, 0, 5};

b = find(a);

c = find(a > 1);

d = a[b];

returns the following:

b == {1, 3}

c == {3}

d == {1, 5}

Example:

a = {{1, 2, 3}, {4, 5, 2}, {2, 8, 9}}

b = find(a == 2);

c = a[b];

b and c return:

b == {3, 4, 8}

c == {2, 2, 2}

Example:

The following statement:

(r, c) = find(a == 2)

returns:

r == {3, 1, 2}

c == {1, 2, 3}

Example:

(r, c, v) = find((a>=5)*a)

r == {2, 3, 3}

c == {2, 2, 3}

v == {5, 8, 9}

Example:

W1: gsin(1000, 1/1000, 1)

W2: find(w1 > 0.5)

W3: find(w1 > 0.5, 1)

W2 == 85..417

W3 == {85}

W2 returns the indices of the samples in W1 where the sine wave amplitude exceeds 0.5.

W3 returns the index of the first sample where the amplitude exceeds 0.5.

Remarks:

As indicated by the second example, FIND returns the indices of the non-zero elements of array as a single "unraveled" series. These indices can be used to address arrays.

If first is 1, the index of the first non-zero element is returned, often resulting in faster searches.

See Also:

DELETE

FINDHANDLE

FINDMAX

FINDMIN

FINDVAL

LOGICAL

RAVEL

REMOVE

SERMATCH

UNRAVEL