RegEx replacing nulls with empties - why?

[G1]

Can anyone explain why this regex replace expression would turn nulls into empties? Pictures attached too.

regex_replace([Field1], '\s+', ' ')

Thanks in advance!

[mpennington · Accepted solution]

Sometimes the RegEx match and replace formulas can be a bit tricky to get to behave exactly as you would intend.  In this case, I would recommend just adding a test for nulls.

IIF(IsNull([Field1]),Null(), REGEX_Replace([Field1], '\s+', '')

I think the output of a RegEx  formula wants to be a string, so that may override Nulls, if I am correct.   Not entirely sure, but an easy workaround. 

[apathetichell · Accepted solution]

I believe "" or empty is the default for an unmatched text regex_replace in the formula tool - so since nothing is done/the formula returns "" - it puts "" in the cell.

If you do a regex_count for your same formula you'll see that it isn't recognizing the null() field as "\s+"

As a workaround you can do an if [field1]=null() then null() else regex... or the cooler iif as recommended by @mpennington 

[G1]

Thanks for responding. Yes, it's an odd behavior. Will have to add the workaround!