Cannot use an If-statement with multiple conditions (AND/OR) when looping through variant array?

Question

Background:

In working with some variant arrays to sort data to multiple locations based on criteria, I noticed that using an if-statement with mult

Answer 1

InStr returns an index. As a logical operator, And wants to have Boolean operands. Given Integer operands, the And operator is a bitwise operator - truth be told, these operators are always bitwise; we just dub them "logical" operators when the operands are Boolean.

If InStr(ex_arr(i, ex_lc), "CriteriaA") Then

This condition is implicitly coercing the returned index into a Boolean expression, leveraging the fact that any non-zero value will convert to True.

Problems start when you bring logical/bitwise operators into the equation.

If InStr(ex_arr(i, ex_lc), "CriteriaA") And InStr(ex_arr(i, 4), "CriteriaB") Then dc(ex_arr(i, 2)) = ex_arr(i, 3)

Say the first InStr returns 2, and the second returns 1. The If expression becomes If 2 And 1 Then, so 0. That's zero, so the condition is false.

Wait, what?

Think of the binary representation of 2 vs that of 1:

  2:  0010
  1:  0001
AND:  0000

Bitwise-AND yields 0, since none of the bits line up.

---

Stop abusing implicit type conversions, and be explicit about what you really mean. What you mean to be doing, is this:

If (InStr(ex_arr(i, ex_lc), "CriteriaA") > 0) And (InStr(ex_arr(i, 4), "CriteriaB") > 0) Then dc(ex_arr(i, 2)) = ex_arr(i, 3)

(redundant parentheses for illustrative purposes only)

Now this evaluates two Boolean expressions, applies bitwise-AND to the two values, and correctly works as intended.

True: 1111
True: 1111
 AND: 1111