Converts numeric values to the missing value code according to the values given in a logical expression.
x (NxK matrix) – data
mask (NxK logical matrix) – (matrix of 0’s and 1’s) that serves as a “mask” for x; the 1’s in mask correspond to the values in x that are to be converted into missing values
y (NxK matrix that equals x) – but with those elements that correspond to the 1’s in e converted to missing.
// Set seed for repeatable random numbers rndseed 49728424; x = rndu(3, 2); // Logical expression mask =(x .> .30) .and (x .< .60); y = missex(x, mask);
After the code above:
0.525 0.419 1 1 . . x = 0.869 0.973 mask = 0 0 y = 0.869 0.973 0.021 0.357 0 1 0.021 .
A 3x2 matrix of uniform random numbers is created. All values in the interval (0.30, 0.60) are converted to missing.
The matrix e will usually be created by a logical expression. For instance, to convert all numbers between 10 and 15 in x to missing, the following code could be used:
y = missex(x, (x .> 10) .and (x .< 15));
Note that “dot” operators MUST be used in constructing the logical expressions.
For complex matrices, the missing value code is defined as a missing
value entry in the real part of the matrix. For complex x, then,
replaces elements with a “. + 0i” value.
This function is like
miss(), but is more general in that a range of
values can be converted into missings.