Add example for fs2-data-csv #16
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Adding/removing a field and printing that out? Calculating and printing the max/min/mean for a specific column? |
| * [Circe] and http4s integration | ||
| * [Decline Effect] | ||
| * [Munit Cats Effect] | ||
| * [fs2-data-csv] |
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Wasn't this the line you added in another PR? :D
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Yes that's me haha!
But somehow a second fs2-data mention got sneaked in:
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lol I've just realized it's a duplicate
Well this is awkward, I don't know how to do aggregation on columns, I want to print out the mean of the ages column using fs2. Do I use a |
I'll say something like val (a,b) = listOfNumbers.foldLeft((0,0)){ case ((s, n), x) => (s + x, n + 1) }
a/b |
| val meanIO = | ||
| input | ||
| .foldMap(p => (p.age.getOrElse(0), 1)) | ||
| .compile | ||
| .lastOrError | ||
| .map((sum, count) => sum / count) | ||
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| input | ||
| .evalTap(p => | ||
| IO.println( | ||
| s"${p.firstName} is taking flight: ${p.flightNumber} to ${p.destination}" | ||
| ) | ||
| ) | ||
| .compile | ||
| .drain >> meanIO.flatMap(mean => | ||
| IO.println(s"The mean age of the passengers is $mean") |
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If there is any way to do this in one run I'd love to know!
The only thing I could think of is chucking a IO.println and flatmapping in the foldMap
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I am a bit late on that, but can't you put the evalTap right before the foldMap, and then compile and run
.flatMap { (sum, count) =>
IO.println(s"The mean age of the passengers is ${sum / count}")
}?
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@satabin feel free to propose a neater implementation. Now it should be easier as toolkit contains fs2-data-csv too :D
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Anybody else know something more exciting to do than printing out the parsed lines of a CSV?