Conditionally combine/write contents from cells

[CatawbaRiverkeeper]

I am working with tens of thousands of lines, and what I need is a function that looks at column A for a certain value (e.g., shirt). For the multiple rows with "shirt" in column A, I need it to look for colors in column B (e.g., red, blue, yellow, green). Then, in like cell D1, I would have "shirt" and in E1 would be "red, blue, yellow, green".

My trick is to get everything written into one cell, as well as to add commas/spaces between the entries. Using this scenario, I'll also have rows with "pants" and other clothing, so I will need a single summary cells for all the colors of each clothing item. I imagine this will be somewhat like a vlookup, but I just need to figure out it.

Thank you!

[natefarm]

Will your data be sorted by item?