Identify only FIRST example(s) of "1" in columnar data where "1" may occur contiguously

[Bebbspoke]

Excel problem currently defying all rational logic and work-round attempts...

ONE column (generated by legit data from various other columns) procures a string of CORRECT data - simply as "1" (true) or "0" or "False" OK great! it's what I wanted... but now I want a NEW column to flag only the first occurence in contiguous string of 1's - isloated occurences of 1's must still be flagged, but where 2 or more 1's are sequential ONLY the first 1 in the sequence is to be flagged... repeated also in later recurrent "strings of 1's" your suggestions please... cheers

Second request - can anyone please send me a link to a full set of syntax rules for Excel formulae? - it seems to defy all rational logic including Boolean!

Thank you

[Ron Coderre]

Can you post some sample data and the results you want (based on that sample) so we'll have a better idea of what you're working with?

[Bebbspoke]

Cheeky - thank you for your response - I have attached a simple example; -

Column A is the raw data and column B is a manually created example of my requirement.

Thank you.

[nemo74]

Hey there,
So I'm new to Excel and this forum, but I wanted to take a crack at this problem. This is what I figured out:

Paste B2 Down and Up. IF you copy it right to B1 it will #REF.

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[Bebbspoke]

Solution is: - =IF(A2=1,IF(A1<>1,1,""),"")

[nemo74]

Solution is: - =IF(A2=1,IF(A1<>1,1,""),"")

That won't work. It's close but I think you wanted to say: =IF(A2=1,IF(A1<>1,1,""),"") Which is shorter than mine; but does not fill in the rest. Still A1 will #ref.

[Bebbspoke]

Thanks for your comment Nemo - but the solution I gave DOES work - I'm not going to discuss why you doubt it. - I am happy with the function.

PLEASE - will somebody produce link to all formulae syntax? - It would fractionate the time wasted on sites such as this, thank you.

[Ace_XL]

Forgetting B1, maybe this shorter formula..

=IF(AND(A2=1,A1<>1),1,"")

[Bebbspoke]

Thanks Ace - satisfied with solution obtained