Concatenation array operator

A[2], ZCat[0] and Reg File[3] are examples of bit-selects. The concatenation operator,, is used to generate a bigger array. 

The Sub procedure shown in Figure 15-1 reads values from worksheet cells and writes them to elements of a VBA array by means of a loop. Either the Cells method or the Range method can be used in the example that follows, the Range method is used, with the concatenation operator, to access the appropriate cell in the range. In this example the values to be copied are in column A, beginning in row 2. To illustrate an additional point, the values extend down to a row that must be determined by the VBA code. 

The system being described in Figure 2-3 is a Kalman filter, a realtime controller consisting of several loops implementing matrix multiplication and other operations. The input to the system is the y array, and the output is the v array. First to be described are the carriers that will take part in the computation. Second, the procedures that specify the actions on the variables are listed. In this case, there is only one procedure (filt) consisting of several nested, labeled blocks and repeat loops. The "Imain)" qualifier indicates that filt is the starting point for execution. A quote mark (") indicates a hexadecimal constant, labeled blocks are named with a colon-equal ( =), and the is the binary concatenation operator. 

Box 5.2 demonstrated how elements and slices of arrays can be used in assignment statements. The concatenation operator and shift operators can also be used in the same way as was illustrated in Box 5.3. Any of these manipulation techniques can be combined with others to make a more complex expression. For example/ using (he declarations from Box 5.2, arrays could be constructed as follows ... 

Note the use of parenthesis around the logical function. Without these around the And operation the expression will be incorrectly evaluated. Both these expressions contain strings of characters enclosed in double quotes that are used to represent bit patterns. These examples illustrate binary representations but octal and hexadecimal formats may also be used (see Box 5.5). Using the concatenation operator to construct array expressions is only one approach. It is also possible to use aggregate expressions that take the form ... 

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