Excel Search returns #Value, but embedded in "Lookup" it works - why? - excel

Question

This links to question 12299700 - I want to understand why SEARCH returns #Value when used alone but works when embedded into LOOKUP, and how I can make it work alone:
In Cell A1 I have a string of text: "This is some sample text"
In Cells D1:D4 I have words: "text, sample1, sample2, string" (all in separate cells)
I want to see if my string contains any of the words in my range - I don't need the matching word/s returned.
Using the Search function in any empty cell in Row 1 =SEARCH($D$1:$D$4,A1), returns 22. Good!
Using this in any other row returns #VALUE. Why?
If I keep my formula in Row 1, but move my range of words down to D2:D5, I get #Value. Why?
How can I make SEARCH work for my cell and ranges, in any cell?
(From the answer to question 12299700 I know I can use this formula to return the matched text, in any cell of the spreadsheet: =LOOKUP(2^15,SEARCH($D$1:$D$4,A1),$D$1:$D$4) - this includes a term that gives #VALUE on its own ... intriguing).
First question asked on Stackoverflow - feedback appreciated.

Answer 1

The function SEARCH returns #VALUE if the searched string was not found within the text. The function SEARCH expect only one searched string. It is not a array function itself. So if it gets a range as searched string, it uses only one of these range values as searched string. Which one it is, depends on the position of the formula.
Within LOOKUP the case is completely different. LOOKUP is an array formula itself. It gets the SEARCH($D$1:$D$4,$A$1) as { SEARCH($D$1,$A$1), SEARCH($D$2,$A$1), SEARCH($D$3,$A$1), SEARCH($D$4,$A$1) } which results in a array like { #VALUE, 21, #VALUE, 21 } depending of if SEARCH finds the string or not. That LOOKUP even works with such an array is strange. Normally it needs a sorted array. But it works and gets the last value which is lower or equal than the searched value.
If you need to use SEARCH like an array formula outside a native array formula, then you have to create this array context by entering the formula with [CTRL]+[SHIFT]+[ENTER] instead of only [ENTER]. The formula gets then curly braces around it.
In my example I have created such a formula in Cell E10.
If you are interested in how formulas work, you should often click fx and look how the single parameters comes through. And you should often use Evaluate Formula on the Formulas tab, in the Formula Auditing group.

Answer 2

What happens is that SEARCH is being used in an array form and is outputting in a linear form (non-array).
So, what happens in row 1 is that you're actually doing:
=SEARCH($D$1,A1)
Because evaluating a linear formula with an array tends to take the value from the array in the same row/column depending on the situation. So that means the above is looking for text in A1 which can be found.
On the second row, you will get:
=SEARCH($D$2,A1)
Which means it is searching for sample1 from A1 and since it cannot be found, you get #VALUE!.
To evaluate an array formula as an array, you will have to use Ctrl+Shift+Enter instead of pushing Enter after typing in the formula. Now the problem is that the formula above will return the same thing if you use only 1 cell...
If you want to see if your string contains any of the words in your range (and it's not important to know what word was found), then you will have to use another function along with SEARCH, for example, SUM and ISNUMBER and evaluating it as an array formula:
=SUM(ISNUMBER(SEARCH($D$1:$D$4,A1)))
And if you get a number above 0, you know there's at least 1 word in the text. Maybe to make the output more explicit:
=IF(SUM(ISNUMBER(SEARCH($D$1:$D$4,A1)))>0, "Word(s) found!", "No words found...")
If you want to know what word was found, you will have to use it as a normal formula and drag it down:
The reason why it works in VLOOKUP is that this function actually expects an array as the second parameter and since SEARCH is returning an array, well, that works out just well.
Also, you can view how functions work by clicking on the cell with the function, then do to 'Formulas' in the menu bar and clicking on 'Evaluate formula':
From there you can see if something is being evaluated as a linear or array formula and see how cell references are being substituted with the actual values.