An Array of Object Variables

For an array of object variables, you must use a different approach to obtain the upper or lower bounds of the array indices, thus ar.Rows.Count 

MsgBox Now changing fifth array element to zero.  

MsgBox Confirming that fifth array element = TestArray(5) MsgBox Please examine fifth array element on worksheet.  

There is an important difference between equating a range of cells in a worksheet to a simple variable in VBA, thus  

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Equating a variable in VBA to a worksheet range automatically creates an array in VBA in which each array element contains the value stored in the cell. Using the Set command to equate an object variable in VBA to a worksheet range automatically creates an array of "cell" objects in VBA. If you change the value of one of the array elements by means of your VBA code, the value in that cell in the worksheet will change, as illustrated by the Sub procedure in Figure 15-3. 

The data shown in Table 7 comprise a portion of a multi-element analysis of mineral water samples. The data from such an analysis can conveniently be arranged in an n by m array, where n is the number of objects, or samples, and m is the number of variables measured. This array is referred to as the data matrix and the purpose of using matrix notation is to allow us to handle arrays of data as single entities rather than having to specify each element in the array every time we perform an operation on the data set. Our data matrix can be denoted by the single symbol X and each element by Xy, with the subscripts i and j indicating the number of the row and column respectively. A matrix with only one row is termed a row vector, e.g., r, and with only one column, a column vector, e.g., c. 

For a three-way array of liquid-chromatography-ultraviolet spectroscopy data, the samples are the objects whereas the absorbance at different retention times (of the chromatography mode) and the wavelengths (of the ultraviolet spectroscopy mode) are the two variable modes. Hence, absorbance is measured as a function of two properties retention time and wavelength. For a three-way array of food products x judges x sensory properties, the judge mode can be an object mode or a variable mode. In a preliminary analysis the judges... 

Some three-way models do not take the nature of a way into account, but the concepts of objects and variables are important, e.g., for defining how an array is preprocessed and for interpretation of the results. The same naturally holds for two-way analysis methods. 

Multivariate Image Analysis Strong and Weak Multiway Methods Strong and weak -way methods analyze 3D and 2D matrices, respectively. Hyperspectral data cube structure is described using chemometric vocabulary [17]. A two-way matrix, such as a classical NIR spectroscopy data set, has two modes object (matrix lines) and V variables (matrix columns). Hyperspectral data cubes possess two object modes and one variable mode and can be written as an OOV data array because of their two spatial directions. 

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