[SOLVED] Find & Replace absolute newbie question

[Economix]

This is my first post and first "technical" issue with open office calc.

I am pre-processing a data file to submit to a machine-learning program. I have a "date" column that looks like

2008-01-03-23-49
0
2008-01-04-01-32
2008-01-04-02-13
0
0
-----etcetra--------

The etcetra is there because there are about 63000 observations (rows). I would like this "date" columns to look like

2008-01-03-23-49
?
2008-01-04-01-32
2008-01-04-02-13
?
?
-----etcetra--------

as the "?" is how the data mining software I will be using understands a "missing value". The problem is, when I use the Find & Replace method, I end up with

2??8-?1-?3-23-49
?
2??8-?1-?4-?1-32
2??8-?1-?4-?2-13
?
?
-----etcetra--------

which will be unacceptable by the data mining software. Any ideas of how I can get "surgical" with the Find & Replace method? Any help is appreciated...thanks!!

Edit: Not to mention, when I put 0 by itself into the Find field, even though I selected the column I wanted the changes performed on, it alters ALL of the 0s throughout my spreadsheet. Can I have it only do this to the column I select specifically?

Also, can anyone direct me to any resources specifically detailing the Find & Replace features, since I am sure I'll be making a heavy amount of use of this feature. Thanks again!

[JohnV]

Find & Replace:
Search = ^0$
Replace = ?
Under More Option check Regular Expressions
Replace All

[Economix]

Thanks JohnV! That was exactly what I was looking for...any idea about the addendum to my question? For now, I am going to scour this forum to see there are any other threads related to this question.

Thanks again!

[JohnV]

[Economix]

Excellent!! Thanks once again, JohnV. You are very helpful. Since we're on this topic - I spent the greater part of today attempting to do one more alteration to my OOo data set. There exists a column which contains (in each of its cells) 2 words separated by a single space. Is there a way I can eliminate the space between them, thus creating a column of just one word in each of the cells?

I have tried using the Find & Replace methodology with Find: \n and Replace with: Replace all (I saw this in another thread I stumbled upon during my search). It didn't work, though.

Any ideas?? Thanks again!

[Economix]

Well, I entered [:space:] in the "Find" field, and it worked, but I am not sure what to put in the replace field yet...maybe I'll try [:space:]{0} and see if it works...

[edit] It didn't work...but I changed [:space:]{0} to an empty field and it worked!!!

Thanks you JohnV!!!