I've got a huge array of data (approx 13,000 rows X 15 columns). I'm looking
for a formula to replace the blank cells as I don't want to copy-paste
13,000 rows. I need the formula to look up the column to find the ID number.

The first column of data contains patient ID numbers. However, there
are blank cells beneath each unique patient ID number until another
unique ID is used. Cells that are adjacent to the blank
ID cells contain data. Is there a formula I can use in Column A to fill in
the blank cells (or lookup and copy the ID number)? Is there VBA code that I
can use?

Here's my data set with the blank cells. My desired result is below.
(col A) (col B)
ID Result
101 Happy
blank Sad
blank Happy
102 Sad
blank Sad
blank Happy
blank Happy
blank Happy

Here's my desired result which replaces the blank cells with the appropriate
ID number.
(col A) (col B)
ID Result
101 Happy
101 Sad
101 Happy
102 Sad
102 Sad
102 Happy
102 Happy
102 Happy

Thanks in advance for your help.

-Scott