marioalvial
Get specific key and the rest of map with Pattern Matching in Elixir
Im trying to get one element and the rest of the map with pattern matching but I’m only get compile errors.
I came up with this:
%{“One” => one | tail} = %{“One" => 1, "Three" => 3, "Two" => 2}
But I got compile errors saying that it was expected key-value pairs.
The behavior that I’m trying to achieve is:
%{“One” => one | tail} = %{“One" => 1, "Three" => 3, "Two" => 2}
one = 1
tail = %{"Three" => 3, "Two" => 2}
In elixir there is a way to acomplished that?
Marked As Solved
Also Liked
dorian-marchal
A bit late to the party, but if you want to pattern match in a function definition, you can also capture the whole map:
defmodule Foo do
def foo(map = %{"One" => one}) do
rest = Map.delete(map, "One")
IO.inspect(%{one: one, rest: rest})
end
end
Foo.foo(%{"One" => 1, "Three" => 3, "Two" => 2})
# > %{one: 1, rest: %{"Three" => 3, "Two" => 2}}
joaoevangelista
Note that you get that error because on %{"One" => one | tail} the | is used to update the key, in your case is like that you are trying to update the tail key but missing the value.
Popular in Questions
Other popular topics
Latest on Elixir Forum
Sponsor Spotlight
Build Elixir applications with speed and confidence.
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
- #channels
- #elixirconf
- #exunit
- #discussion
- #code-sync
- #javascript
- #podcasts
- #onsite
- #dialyzer
- #docker
- #authentication
- #umbrella
- #full-time-contract
- #podcasts-by-brainlid
- #ecto-query
- #elixir-ls
- #phoenix_html
- #iex
- #blog-post
- #graphql
- #genstage
- #ai
- #websockets
- #supervisor
- #advent-of-code
- #elixirconf-us
- #distillery
- #processes
- #forms
- #api
- #metaprogramming
- #security
- #performance
Our Sponsors
Build Elixir applications with speed and confidence.
Supporting innovation across the BEAM ecosystem.
We build reliable cloud platforms for business-critical systems.
Catch errors, track performance, monitor hosts and more.
Error tracking for Elixir devs who love to ship. Start your free account.
Practical resources that improve the lives of professional developers.
Develop your skills with books, videos, and courses.
Producing high quality Elixir screencasts since 2017.
The team behind Membrane, Popcorn, LiveDebugger. Available for hire.
Courses that'll move you from confusion to "Aha, now I get it!"