Utility Functions

Hlookup(z, A, r, modifier) Takes a real input z, an array A of mixed real, complex, or string values, and a comparison criterion modifier. Hlookup matches z in the first row of A, subject to the conditions of modifier, and returns the result(s) in row r in the same columns as the matched elements.

z must be a scalar, unless you specify "range" as the comparison criterion, in which case it can be a 2-element column vector.

Lookup(z, A, B, modifier) Takes a real input z, two arrays A and B of mixed real, complex, or string values, and a comparison criterion modifier. Lookup matches z in A, subject to the conditions of modifier, and returns the value(s) in the same position(s) (that is, with the same row and column numbers) in matrix B.

z must be a scalar, unless you specify "range" as the comparison criterion, in which case it can be a 2-element column vector.

Match(z, A, modifier) Takes a vector or matrix A of real, complex, or string values, a real input z to search for in A, and a comparison criterion modifier, and returns a vector of indices for all matching elements in A.

z must be a scalar, unless you specify "range" as the comparison criterion, in which case it can be a 2-element column vector.

VHlookup(z1, z2, A, modifier) Takes two values z1 and z2, an array A of real, complex, or string values, and a comparison criterion modifier. VHlookup matches z1 in the first column of A and z2 in the first row of A, and returns the value at the intersection, subject to the conditions of modifier.

With VHlookup, either z1 or z2 can be a string, but not both. If either is a string, an exact match must be made in the corresponding row/column of A.

vhlookup(z1, z2, A) Takes two values, z1 and z2, and an array A of real, complex, or string values. vhlookup matches z1 in the first column of A and z2 in the first row of A, and returns the value at the intersection. The accuracy of the match is controlled by TOL.

Vlookup(z, A, c, modifier) Takes a real input z, an array A of mixed real, complex, or string values, and a comparison criterion modifier. Vlookup matches z in the first column of A, subject to the conditions of modifier, and returns the result(s) in column c in the same rows as the matched elements.

z must be a scalar, unless you specify "range" as the comparison criterion, in which case it can be a 2-element column vector.

Comparison Modifiers for Match and Lookup Functions

The following modifiers are supported by the Match and lookup functions provided as part of the Data Analysis Extension Pack:

localmax(M, [w]) Takes a real n x 2 matrix M and optional integer w, ≥ 1, and finds the local maxima in the second column of M. w (window width) is optional, and defaults to 1; for w > 1, each point in the data must be greater than the surrounding (2w + 1) points to be considered a local maximum to avoid false positives from noise. Function returns a 2-column matrix of the x and y values for each maxima.

localmax(x, y, M, [w]) The 3D version of this function takes vectors of x and y coordinates, a matrix of associated z values, M, and performs the same search for local maxima by nearest-neighbor comparison. M must have the same number of rows as x, and the same number of columns as y has rows.

localmin(M, [w]) Takes a real n×2 matrix M and optional integer w, ≥ 1, and finds the local minima in the second column of M. w (window width) is optional, and defaults to 1; for w > 1, each point in the data must be less than the surrounding (2w + 1) points to be considered a local minimum. Function returns a 2-column matrix of the x and y values for each minima.

localmin(x, y, M, [w]) The 3D version of this function takes vectors of x and y coordinates, a matrix of associated z values, M, and performs the same search for local minima by nearest-neighbor comparison. M must have the same number of rows as x, and the same number of columns as y has rows.