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Comment by nxpnsv | Hacker News Reader

I don't know if

   result = (df
      .pipe(fun1, arg1=1)
      .pipe(fun2, arg2=2)
   )

is much less readable than

   result <- df |> 
      fun1(., arg1=1) |> 
      fun2(., arg2=2)

but I guess the R thing also works beyond dataframes which is pretty cool

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The pipe operator uses what comes before as the first argument of the function. This means in R it would be:

    result <- df
      |> fun1(arg1=1)
      |> fun2(arg2=2)

Python doesn't have a pipe operator, but if it did it would have similar syntax:

    result = df
      |> fun1(arg1=1)
      |> fun2(arg2=2)

In existing Python, this might look something like:

    result = pipe(df, [
      (fun1, 1),
      (fun2, 2)
    ])

(Implementing `pipe` would be fun, but I'll leave it as an exercise for the reader.)

Edit: Realized my last example won't work with named arguments like you've given. You'd need a function for that, which start looking awful similar to what you've written:

    result = pipe(df, [
      step(fun1, arg1=1),
      step(fun2, arg2=2)
    ])

Python supports a syntax like your first example by implementing the appropriate magic method for the desired operator and starting the chain with that special object. For example, using just a single pipe: https://flexiple.com/python/python-pipeline-operator

The functions with extra arguments could be curried, or done ad-hoc like lambda v: fun1(v, arg1=1)

>Implementing `pipe` would be fun, but I'll leave it as an exercise for the reader.

I like exercise:

https://gist.github.com/stuarteberg/6bcbe3feb7fba4dc2574a989...

Neat!

Thanks!

I find this (hypothetical) syntax *very* elegant.

    result = df
      |> fun1(arg1=1)
      |> fun2(arg2=2)

I haven't used R in forever, but is your `.` placeholder actually necessary? From my recollection of pipe operator the value being pipe piped is automatically as the first argument to the next function. That may have been a different implementation of a pipe operator though.

Probably not, I didn’t use R much during the last decade …

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