[R] Pipe operator

[Sorkin, John]

Jeff,
Thank you for contributing important information to this thread. 

________________________________________
From: Jeff Newmiller <jdnewmil using dcn.davis.ca.us>
Sent: Tuesday, January 3, 2023 2:07 PM
To: r-help using r-project.org; Sorkin, John; Ebert,Timothy Aaron; 'R-help Mailing List'
Subject: Re: [R] Pipe operator

The other responses here have been very good, but I felt it necessary to point out that the concept of a pipe originated around when you started programming [1] (text based). It did take awhile for it to migrate into programming languages such as OCaml, but Powershell makes extensive use of (object-based) pipes.

Re memory use: not so much. Variables are small... it is the data they point to that is large, and it is not possible to analyze data without storing it somewhere. But when the variables are numerous they can interfere with our ability to understand the program... using pipes lets us focus on results obtained after several steps so fewer intermediate values clutter the variable space.

Re speed: the magrittr pipe (%>%) is much slower than the built-in pipe at coordinating the transfer of data from left to right, but that is not usually significant compared to the computation speed on the actual data in the functions.

 [1] https://nam11.safelinks.protection.outlook.com/?url=https%3A%2F%2Fen.m.wikipedia.org%2Fwiki%2FPipeline_&data=05%7C01%7Cjsorkin%40som.umaryland.edu%7C94e1ec7b93c642286aae08daedbdc79f%7C717009a620de461a88940312a395cac9%7C0%7C0%7C638083696601759531%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C3000%7C%7C%7C&sdata=gdooVKcK8iDNN0X6ZaYmDNk9pQ1Pe%2BgQiUGioPGB%2Fps%3D&reserved=0(Unix)#:~:text=The%20concept%20of%20pipelines%20was,Ritchie%20%26%20Thompson%2C%201974).

On January 3, 2023 9:13:22 AM PST, "Sorkin, John" <jsorkin using som.umaryland.edu> wrote:
>Tim,
>
>Thank you for your reply. I did not know about the |> operator. Do both %>% and |> work in base R?
>
>You suggested that the pipe operator can produce code with fewer variables. May I ask you to send a short example in which the pipe operator saves variables. Does said saving of variables speed up processing or result in less memory usage?
>
>Thank you,
>John
>
>________________________________________
>From: Ebert,Timothy Aaron <tebert using ufl.edu>
>Sent: Tuesday, January 3, 2023 12:07 PM
>To: Sorkin, John; 'R-help Mailing List'
>Subject: RE: Pipe operator
>
>The pipe shortens code and results in fewer variables because you do not have to save intermediate steps. Once you get used to the idea it is useful. Note that there is also the |> pipe that is part of base R. As far as I know it does the same thing as %>%, or at my level of programing I have not encountered a difference.
>
>Tim
>
>-----Original Message-----
>From: R-help <r-help-bounces using r-project.org> On Behalf Of Sorkin, John
>Sent: Tuesday, January 3, 2023 11:49 AM
>To: 'R-help Mailing List' <r-help using r-project.org>
>Subject: [R] Pipe operator
>
>[External Email]
>
>I am trying to understand the reason for existence of the pipe operator, %>%, and when one should use it. It is my understanding that the operator sends the file to the left of the operator to the function immediately to the right of the operator:
>
>c(1:10) %>% mean results in a value of 5.5 which is exactly the same as the result one obtains using the mean function directly, viz. mean(c(1:10)). What is the reason for having two syntactically different but semantically identical ways to call a function? Is one more efficient than the other? Does one use less memory than the other?
>
>P.S. Please forgive what might seem to be a question with an obvious answer. I am a programmer dinosaur. I have been programming for more than 50 years. When I started programming in the 1960s the only pipe one spoke about was a bong.
>
>John
>
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--
Sent from my phone. Please excuse my brevity.