Working from the inside out, the ISNUMBER function will return TRUE when given a number and FALSE if not. When you supply a range to ISNUMBER (i.e. an array), ISNUMBER will return an array of results. In the example, the range C5:C9 contains 5 cells, so the array returned by ISNUMBER contains 5 results:
TRUE values represent numeric values.
We want to know if this result contains any TRUE values, so we use the double negative operator (--) to force the TRUE and FALSE values to 1 and 0 respectively. This is an example of boolean logic, and the result is an array of 1's and 0's:
To determine if a value exists in a range of cells, you can use a simple formula based on the COUNTIF function. In the example shown, the formula in D5 is: = COUNTIF ( rng , B5 ) > 0 where "rng" is the named range F4:F10. How this formula works...
The SUMPRODUCT function multiplies ranges or arrays together and returns the sum of products. This sounds boring, but SUMPRODUCT is an incredibly versatile function that can be used to count and sum like COUNTIFS or SUMIFS, but with more...
The Excel ISNUMBER function returns TRUE when a cell contains a number, and FALSE if not. You can use ISNUMBER to check that a cell contains a numeric value, or that the result of another function is a number.
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