# Joining multi-valued cells as an expression

**URL:** <https://forum.openrefine.org/t/joining-multi-valued-cells-as-an-expression/1670>\
**Category:** Data cleaning and transformations\
**Created:** [July 26, 2024, 9:53am UTC](https://forum.openrefine.org/t/joining-multi-valued-cells-as-an-expression/1670 "2024-07-26T09:53:41Z")\
**Posts on this page:** 3\
**Page:** 1

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**Author:** ![grahamjevon](https://dub1.discourse-cdn.com/flex017/user_avatar/forum.openrefine.org/grahamjevon/32/105_2.png) [@grahamjevon](https://forum.openrefine.org/u/grahamjevon)\
**Post date:** [July 26, 2024, 9:53am UTC](https://forum.openrefine.org/t/joining-multi-valued-cells-as-an-expression/1670/1 "2024-07-26T09:53:41Z")

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Hello

Individual columns have a menu option to "join multi valued cells". Does anyone know what this looks like as a GREL expression so that I can apply it as a transform to all columns in one action? (I'm lagging behind on v3.2)

Thanks, Graham

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**Author:** ![ostephens](https://dub1.discourse-cdn.com/flex017/user_avatar/forum.openrefine.org/ostephens/32/8_2.png) [@ostephens](https://forum.openrefine.org/u/ostephens)\
**Post date:** [July 26, 2024, 10:57am UTC](https://forum.openrefine.org/t/joining-multi-valued-cells-as-an-expression/1670/2 "2024-07-26T10:57:11Z")

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Hi @grahamjevon. Unfortunately the join multi-valued cells function isn't a front for a GREL expression, but rather coded into the OR software. I think you could write a GREL that did the "join" part in GREL by:

- checking if you are in the first row in the record
  - If yes, populate with a "join()" across all rows in the record
  - If not, set to blank or null

But this would be a relatively complex GREL statement and will leave you with a whole load of blank cells as the blanked rows won't be removed by this GREL

A different approach which might prove a better option would be to create a "history" file that applies the "join multi-valued cells" to each column in turn. This basically looks like:

```auto
[
  {
    "op": "core/multivalued-cell-join",
    "columnName": "Column 2",
    "keyColumnName": "Column 1",
    "separator": "|",
    "description": "Join multi-valued cells in column Column 2"
  },
{
    "op": "core/multivalued-cell-join",
    "columnName": "Column 3",
    "keyColumnName": "Column 1",
    "separator": "|",
    "description": "Join multi-valued cells in column Column 3"
  },
{
    "op": "core/multivalued-cell-join",
    "columnName": "Column 4",
    "keyColumnName": "Column 1",
    "separator": "|",
    "description": "Join multi-valued cells in column Column 4"
  }
]

```

etc. Once you have this JSON (there are of course various ways of creating this), you can apply in via the undo/redo pane as usual

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<div class="post-metadata">

**Author:** ![grahamjevon](https://dub1.discourse-cdn.com/flex017/user_avatar/forum.openrefine.org/grahamjevon/32/105_2.png) [@grahamjevon](https://forum.openrefine.org/u/grahamjevon)\
**Post date:** [July 26, 2024, 11:12am UTC](https://forum.openrefine.org/t/joining-multi-valued-cells-as-an-expression/1670/3 "2024-07-26T11:12:47Z")

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Thanks @ostephens , in that case I'll go for the json option (or export to perform this action in Python and import back to OR).