Skip, ignore or miss false value

I am looking to copy data from one cell to another, only if something is true. If it is false I want it to ignore the false side of things and not leave a blank cell, or put a zero or false. Just to leave the cell as is (as the cell will have data in already that I don't want overwritten.

Please see the attached file.
If any false HAS to be written, could it then write the false output to the blank cell to the right of it?

(Apologies if this has been answered before, I've searched and searched and couldn't find just what I was after, or adjust previous similar results to work for this scenario)

as I see there is another condition
d2 =IF(B1="variable";C1;"")

Originally Posted by BMV

as I see there is another condition
d2 =IF(B1="variable";C1;"")

Hi BMV, yes that's correct.
This is a very small part of csv for a website.

It is for products that are either "simple" - just buying as is or as "variable" where you can buy either a t-shirt in red, green, blue with sizes S, M, L. I need to put the parent product (column D) in for all the variations.
That means I need to pick up the product code (C1) when "variable" is in B1 and then put that into all the variations for that product, in this case into D2, D3 and D4.

One issue is, that when I have "variable" then the "variations" for it can differ from a few to many, hence trying to first copy over from C1 to D2, then after that copy D2 down for each following variation.

Originally Posted by shank_mis

Referring to your sheet, you cannot write formula in column D otherwise you will loose data in stored in that column. I hope that's obvious to you.
In column E, you can write formula and this column would yield final result.

In Cell E2: =IF(AND(D2="",B2="variation"),E1,D2) and drag the formula down to the end.
This would give you desired result. You can hide column D or keep it whatever you like.

Hi Shank_mis,

This is my first proper time of using functions so, no it wasn't obvious that I couldn't put formulas into column D. I've done basic maths formulas but never needed to do something as complex as this. I was hoping that there was a way that an IF function could have its' false value ignored or use another function that only gives out true values.

However, your formula works a treat. I can use that and then copy the contents from column E into D as visual data. Perfect. Thank you SO much. Really appreciated.