EasyConcat - Google Sheets add-on

EasyConcat lets you concatenate many adjacent rows or columns, with a delimiter you choose. Removes extra delimiters automatically!Concatenating is great, but it can be a huge chore, especially if there are lots of columns or you have many empty values. This simple custom function lets you concatenate adjacent cell values with ease. Just use EASYCONCAT after installation. Click and drag across the cells you want to concatenate for the first value (or just type in the range), then specify a delimiter in quotes for the second value.

EasyConcat will ignore empty cells (and your skipvalue, if you specify it), so you won't have a bunch of delimiters in a row. As with most functions, you can, after hitting Enter, drag down from the destination cell to apply to many rows at once. It's so easy!

NEW as of April 2017: concatenate columns as well as rows! Speed enhancements were also implemented.

NEW as of February 2016: an optional "skipvalue" parameter! This feature was requested by a user. Now you can specify an additional value to be considered blank when concatenating. An example would be skipping all cells that only have a 0 in them.