selif¶

Purpose¶

Selects rows from a matrix. Those selected are the rows for which there is a 1 in the corresponding row of e.

y = selif(x, e)¶

Parameters:	x (NxK matrix or string array) – data e (vector) – Nx1 vector of 1’s and 0’s
Returns:	y (MxK matrix or string array) – consists of the rows of x for which there is a 1 in the corresponding row of e.

x = { 112 252,
       99 119,
      109  81,
      184 111,
      209  94 };

 y = selif(x, x[., 2] .> 100);

This example selects all rows of x in which the second column is greater than 100. This will set y equal to:

  252
  119
  111

x = { 0 10 20,
     30 40 50,
     60 70 80 };

e = (x[., 1] .gt 0) .and (x[., 3] .< 100);
y = selif(x, e);

The resulting matrix y is:

30 40 50
60 70 80

All rows for which the element in column 1 is greater than 0 and the element in column 3 is less than 100 are placed into the matrix y.

The argument e will usually be generated by a logical expression using “dot” operators.

y will be a scalar missing if no rows are selected.