function assistance please

Please help!

I am trying to match data in one column to data in another using a formula, however what I have tried does not seem to give me correct results. Here is an example:

COLUMN A COLUMN B
01223343 01223343
01223344 01223344
01223345 01223345
01223346 01223346
01223348 01223347
01223350 01223348

I need to create a formula that indicates that a number in column A is also in column B, using an IF function so I can get a true or false result. The problem I have run into is that, as you see in my example above, the numbers do not necessarily match row for row. My original formula was: =IF(A2=(lookup(A2,b2:b100)),"True","False"). This appeared to work, until the number in cell A6 did not match the number in cell B6, then it came back false even though the number was clearly in the array. Ultimately I am trying get the result spelled out here: If this number is in this column then 'true', if not then 'false'

Any help would be greatly appreciated!!

The suggestion from VBA Noob was the one that worked!!

I wasn't too concerned with locking the range with the $$ signs since my data filled 8,000+ rows, although I appreciated the reminder to add them.

I am not sure why the formula suggestion from pjoaquin didn't work since it does seem to be correct, but I did try it again and I ended up with the same results. For example, the number in cell A55 is 00116675 and I can see it in the lookup array($B$2:$B$1000) in cell B57, however this formula indicates "false" even though it is clearly "true". Funny, huh?! Thank you regardless, pjoaquin, I appreciate the effort!!!

Also, thanks for the very quick responses! I told many co-workers about this site this afternoon. I am sure I will be in need again!

Lisa

LOOKUP needs the lookup range to be sorted ascending, otherwise the results may not be correct.

COUNTIF is fine although you don't really need the IF

=COUNTIF($A$1:$A$10,B1)>0

This will give you TRUE or FALSE by default [although logical values not text values]

....another way, which is probably more efficient (perhaps not relevant here but might be if you had a huge spreadsheet with lots of such formulas)

=ISNUMBER(MATCH(B1,$A$1:$A$10,0))