vals
The |> operator takes the result of the expression on its left and injects it as the first parameter of the function call to its right.
The Regex.replace function signature is this: run(regex, string, options \\ [])
The first argument is the regex.
Then how is it possible the following code to work without error
iex(115)> "cats like catnip" |> String.replace(~r/cat/, "dog") "dogs like dognip" iex(116)>
In the last example it seems that the pipe operator injects the second argument of the function.
Where Next?
Trending in Questions
Other Trending Topics
Latest on Elixir Forum
Sponsor Spotlight
Elixir, Erlang & messaging conferences from Code Sync. Next up: ElixirConf US (10–11 Sep) & Code BEAM Europe (21–22 Oct), Haarlem + online.
Categories:
Sub Categories:
Forums
Popular Tags
- #ecto
- #liveview
- #troubleshooting
- #learning-elixir
- #deployment
- #library
- #erlang
- #testing
- #genserver
- #mix
- #absinthe
- #remote-other
- #otp
- #plug
- #how-to-question
- #macros
- #postgres
- #elixirconf
- #channels
- #exunit
- #discussion
- #code-sync
- #javascript
- #podcasts
- #onsite
- #dialyzer
- #docker
- #authentication
- #umbrella
- #full-time-contract
- #podcasts-by-brainlid
- #ecto-query
- #blog-post
- #elixir-ls
- #elixirconf-us
- #ai
- #phoenix_html
- #iex
- #graphql
- #genstage
- #websockets
- #supervisor
- #advent-of-code
- #distillery
- #processes
- #api
- #forms
- #hex
- #security
- #metaprogramming
Our Sponsors
Build Elixir applications with speed and confidence.
Supporting innovation across the BEAM ecosystem.
We build reliable cloud platforms for business-critical systems.
Error tracking, logs, uptime, and Just Enough APM. Built for developers.
Elixir, Erlang & BEAM conferences from Code Sync - join us in 2026!
Master modern tools, write cleaner code, and tackle real-world challenges.
Bringing learning, work and compliance together since 1987.
The deployment platform built for Elixir: PaaS ease, VPS control.
The team behind Membrane, Popcorn, LiveDebugger. Available for hire.
Courses that'll move you from confusion to "Aha, now I get it!"
Showing Posts 1 to 5- Show Best Posts
- Show All (oldest first)
- Show All (newest first)
NobbZ
I do not get your question…
The typespec for
Regex.replace/4isreplace(Regex.t, String.t, String.t | (... -> String.t), [term]) :: String.t, which has nothing to do withRegex.run/3.The typespec for
String.replace/4isreplace(String.t, pattern | Regex.t, String.t, keyword) :: String.t, and this is what you actually used iniex.wmnnd
String.replace/3is not the same asRegex.replace/3.While
String.replace/3takes a string first,Regex.replace/3takes a regular expression instead.Take a look at the differences in the documentation of the two functions:
vals
Oops! Obviously, it was my blunder.
String.replace/4is a different function thanRegex.replace/4.However, while I was searching for an answer I bump upon this suggestion Joe Armstrong on X: "#eliixir How about |N> meaning inject in to the N'th arg of the next function? |> is short hand for |1> (|N> is "joes" operator :-)" / X
NobbZ
The numbered pipe has been discussed before, I do consider it as unreadable.
But there is
param_pipeavailable on hex. Announcement and discussion is available on the forum as well:cjen07
Haha, I am just too busy to do any upgrades currently.