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kotlinlang

Hi friends! DataFrame question. :slightly_smiling_face:  I have a `.csv` file in which one the columns has a comma-separated string. I would like to split it and have the line replicated for each element. I have a working code, but it's far from optimal. Code in thread. :thread:

So far, I move back and forth from data class to DataFrame, but it seems very inefficient:

```//    ➜ cat test.csv
//    id,list
//    1,"a,b,c"
//    2,"d"
//    3,"e,f"

    data class Thing(val id: Int, val list: String)

    DataFrame
        .readCSV("test.csv")
        .toListOf&lt;Thing&gt;()
        .flatMap { thing -&gt;
            thing.list.split(",").map { thing.copy(list = it) }
        }
        .toDataFrame()
        .print()

//    id list
//    0  1    a
//    1  1    b
//    2  1    c
//    3  2    d
//    4  3    e
//    5  3    f```

Any suggestions are welcome! Thanks! :gratitude-thank-you:

Here you are: <https://gist.github.com/belovrv/859e71684452b6383fbabed30cc2ab5d>

image.png

And with the upcoming compiler plugin even more neat*:* 

This is amazing! :fire: Thank you so much, Roman! :gratitude-thank-you:  Looking forward to the upcoming plugin! Cheers!

Oh, I've forgotten there's easier way
```DataFrame.readDelimStr(csv)
    .split("list").by(',').inplace()
    .explode("list")```