Hello! I think this is probably an easy one for the coders out there; I'm a beginner so looking to the experts for a little help and advice :)

I have a text field Product_Groups__c on the opportunity that is meant to hold a deduplicated, concatenated list of Product_Group__c (picklist) from all of the Line Items on an Opp. So if an opp has 3 line items each with something different in Product_Group__c:

Item 1 | Shirts
Item 2 | Pants
Item 3 | Shoes

The field would populate with "Shirts;Pants;Shoes"  Likewise, if Item 1 and 2 were both Shirts and Item 3 is Shoes, the field would read "Shirts;Shoes" 

We'll be populating this on opps going forward through our integration with our quoting tool... so I just need to be able to populate this on all existing opp records. I only have to do this once, I thought maybe it could be done using anonymous apex? However I'm not sure what the code would be... and I'm also curious about the following:

1. using execute anonymous, would this still register an edit on the record (ie. would last modified change to my name and the date I run this?)
2. can this be done to bypass/ignore triggers and workflows?

I do have a (very large) spreadsheet of our opp ids with a deduplicated list of the Product Groups... but weeding through that to concatenate started to feel a bit more cumbersome than having the system do it for me. Any thoughts/ideas would be a great help!

Thanks