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ELIXIR QUESTIONS

How to have a key value output
How to have a key value output
should help you out If you want to get both the number and the sum of its digits, you should return a tuple or a list in the mapping function, like so:
TAG : elixir
Date : October 29 2020, 08:01 PM , By : karthik chitturi
Ecto.Repo.delete/2: When looking at a type specification, how do you know if there is a default value?
Ecto.Repo.delete/2: When looking at a type specification, how do you know if there is a default value?
wish helps you Browsing through the docs and a similar question's answer, it seems that default arguments are not supported in typespecs. This Github issue from 2014 explains some of the tradeoffs to such a feature. How would one know the second argu
TAG : elixir
Date : October 22 2020, 06:10 AM , By : user6020400
Dialyzer warnings about pattern_match_cov on Gettext module
Dialyzer warnings about pattern_match_cov on Gettext module
hop of those help? As a workaround until the bug is fixed, I made .dialyzer_ignores.exs with the following contents in the root directory of umbrella project.
TAG : elixir
Date : October 19 2020, 06:10 AM , By : zipuniz1999
String concatenation: binary syntax v. operator <>
String concatenation: binary syntax v. operator <>
will be helpful for those in need Yes. The /2 operator is a macro that transforms the code into the special form.
TAG : elixir
Date : October 18 2020, 06:10 PM , By : Sam Iezzi
How to integrate test.watch with `iex -S mix phx.server`
How to integrate test.watch with `iex -S mix phx.server`
this will help Oops, nevermind. Turns out I just needed to increase the inotify limit.
TAG : elixir
Date : October 13 2020, 10:00 PM , By : bakha0000
The task "docs" could not be found. Did you mean "do"?
The task "docs" could not be found. Did you mean "do"?
like below fixes the issue The mix docs task is available with ExDoc. Make sure that you have the dependency installed. Make sure to check out the docs and install it properly. Then you'll be able to use the mix docs command.This is how to install it
TAG : elixir
Date : October 13 2020, 12:00 PM , By : Forevors Design
How can I use Elixir's doctest to test a protocol implementation?
How can I use Elixir's doctest to test a protocol implementation?
it helps some times It turns out that defimpl defines a module behind the scenes. This can be found via the impl_for function on the protocol:
TAG : elixir
Date : October 13 2020, 12:00 PM , By : danny gomez
Elixir: I'm getting an error from a simple addition function
Elixir: I'm getting an error from a simple addition function
I hope this helps . I created a simple function in Elixir that increments a value from a tuple by 1. , In your function definition here:
TAG : elixir
Date : October 13 2020, 08:00 AM , By : Farris Chiew
Can you create conditional plugs in elixir?
Can you create conditional plugs in elixir?
I wish this help you You got it almost right, you only forgot to pass the second argument to call!A module plug is a module with two functions: init/1 and call/2. In order to invoke any module plug dynamically, you need to invoke init/1 with the defa
TAG : elixir
Date : October 13 2020, 02:00 AM , By : Robin
The database for Rumbl.Repo couldn't be created: killed
The database for Rumbl.Repo couldn't be created: killed
it helps some times Your Postgres database is not running or not open on this port. If you don't want to handle with postgres issues or are not familiar with that, take a look on this post about how to have it running on a docker container.
TAG : elixir
Date : October 12 2020, 05:00 PM , By : Iconj
Building association between two tables before inserting
Building association between two tables before inserting
wish of those help As it might be seen from the error message, Repo.get_by/2 returns %Accreditor.Role.Roles{} struct, which has no role field. And you are trying to pass it to the function accepting a parameter that is to be pattern matched on %{role
TAG : elixir
Date : October 12 2020, 12:00 PM , By : b3nschii
Import module from another directory
Import module from another directory
like below fixes the issue I figured out 1 way of doing this but hoping there might be a better way. ...I added -pa argument (which allows you to prepend other paths to the Erlang code path).
TAG : elixir
Date : October 12 2020, 11:00 AM , By : Andrea Cavallaro
Reverse and Concat a List
Reverse and Concat a List
hope this fix your issue I'd say it would be more idiomatic to use the ++ operator instead of Enum.concat. (Note that ++ requires the arguments to be lists, whereas Enum.concat accepts any kind of enumerable.)
TAG : elixir
Date : October 12 2020, 04:00 AM , By : Thiago K
Storing calculated column to use in order_by and select
Storing calculated column to use in order_by and select
Any of those help You could use an alias to reuse that calculated value, although you'll have to use fragments. It's not such a tradeoff! This article details the logic nicely.In your use case, it would give something like this:
TAG : elixir
Date : October 11 2020, 11:00 AM , By : Manny Somarriba
Phoenix Elixir : cannot escape function in elixir compiler
Phoenix Elixir : cannot escape function in elixir compiler
like below fixes the issue cannot escape Function. The supported values are: ... remote functions in the format Mod.fun/arity
TAG : elixir
Date : October 10 2020, 05:00 PM , By : Cecil Owens
Elixir / Phoenix: Why do route helpers require @conn?
Elixir / Phoenix: Why do route helpers require @conn?
wish of those help The connection has additional information beyond the endpoint. For example, if you have two routers in your application, where one calls the other, you need to be able to assemble the original path back together (this is typically
TAG : elixir
Date : October 10 2020, 03:00 PM , By : Qmazed
Elixir / Phoenix LiveView: How can I report exceptions to Rollbar?
Elixir / Phoenix LiveView: How can I report exceptions to Rollbar?
it helps some times But when my LiveView code crashes, I don't get this assurance. The LiveView process will recover from the crash and (as I understand it) revert to its last known healthy state
TAG : elixir
Date : October 10 2020, 09:00 AM , By : Khanssa Bendahmane
Elixir Phoenix not loading env variable at runtime
Elixir Phoenix not loading env variable at runtime
This might help you I am trying to load an API key as a system env from my mac when starting up the phoenix server. What am I getting wrong? these are my steps: , Attributes are evaluated during compilation, so:
TAG : elixir
Date : October 10 2020, 02:00 AM , By : stov
How to clean test DB after **all** test complete?
How to clean test DB after **all** test complete?
To fix the issue you can do You might use ExUnit.Callbacks.on_exit/2:
TAG : elixir
Date : October 09 2020, 06:00 PM , By : Hemant Bharti
Why does ecto can't preload query with 'Group by'?
Why does ecto can't preload query with 'Group by'?
I hope this helps . I'm developping a chat. I have many rooms, withs members in these rooms. Users can also join multiples rooms so it's a many to many relationship. I want to get a room, preload it's members and for each member, count the number unr
TAG : elixir
Date : October 08 2020, 09:00 AM , By : girlgerms
Cannot use Argon2 or Bcrypt with Comeonin, receiving conflicting errors
Cannot use Argon2 or Bcrypt with Comeonin, receiving conflicting errors
seems to work fine I'm using version 5.1.2 of Comeonin to hash passwords. The documentation says that either bcrypt_elixir or argon2 are compatible hashing libraries. The problem I'm encountering happens with both. , I can call:
TAG : elixir
Date : October 07 2020, 04:00 PM , By : techsays24
Elixir: How to push map into Array/list?
Elixir: How to push map into Array/list?
fixed the issue. Will look into that further I have 1 function which I call mutliple times, I wanted to call this function multiple times and put into array/list , The equivalent of your ruby sample in elixir would be:
TAG : elixir
Date : October 07 2020, 10:00 AM , By : haozibi
How to customise the options to the Plug.Parsers JSON decoder?
How to customise the options to the Plug.Parsers JSON decoder?
will be helpful for those in need As well as the module name, it's possible to pass a {Module, :function, args} tuple as the :json_decoder argument. This can be used to customise the arguments to the decoder:
TAG : elixir
Date : October 06 2020, 02:00 PM , By : Hasan Faiz
How to round to the next 1000 value?
How to round to the next 1000 value?
I wish this helpful for you I want to round to the next 1000 value, always rounding up. , Ciel is correct, you need to add some math to it.
TAG : elixir
Date : October 06 2020, 07:00 AM , By : Wongsathorn Phaisarn
Is with and try/rescue can be same in elixir
Is with and try/rescue can be same in elixir
With these it helps with is used when you want to make sure that a number of steps ensure that the right data is available in your application before you can perform the task. A common example would be to make sure that fields exist in a map:
TAG : elixir
Date : October 05 2020, 08:00 PM , By : D'pa
In Elixir, is there any way to make _real_ constants?
In Elixir, is there any way to make _real_ constants?
hop of those help? I find it a little misleading and confusing that while Elixir boasts immutability, that immutability is buried between layers of mutable abstractions. , Could such code be considered idiomatic?
TAG : elixir
Date : October 05 2020, 07:00 PM , By : james kaviti
Why does my Enum.reduce based implementation of Enum.all? return an empty list?
Why does my Enum.reduce based implementation of Enum.all? return an empty list?
Any of those help If you're reducing into a boolean (reduce won't be the best approach here, but it can be done), your accumulator is going to be a boolean, not a list, and each iteration will be a boolean representing "everything prior was true and
TAG : elixir
Date : October 05 2020, 03:00 PM , By : Preeti Gupta
Generating huge report without loading the server to the limit
Generating huge report without loading the server to the limit
To fix this issue Have you considered using Streams to solve your problem? It might help you out.Here's a possibly helpful article about the subject of streams: https://www.poeticoding.com/processing-large-csv-files-with-elixir-streams/
TAG : elixir
Date : October 03 2020, 11:00 PM , By : TABISH ALAM
Can't use generator for the rumbl tutorial project in elixir
Can't use generator for the rumbl tutorial project in elixir
wish of those help Your problem is using functions which is on different versions of Phoenix. This comes from reading old version book of Programming Phoenix (now the latest is 1.4, which update for Phoenix 1.4). You should read the latest book to le
TAG : elixir
Date : October 03 2020, 11:00 AM , By : Brandon Samson
How to share result between multiple concurrent requests in Elixir/Phoenix?
How to share result between multiple concurrent requests in Elixir/Phoenix?
Any of those help Simply wrap the function calling 3rd party service into GenServer.handle_call/3.This process implementing GenServer behaviour would be maintaining queue for free; OTP will do.
TAG : elixir
Date : October 03 2020, 07:00 AM , By : Michael
How do I send data from a child worker process to parent process?
How do I send data from a child worker process to parent process?
Hope this helps There are many issues with your approach. Supervisor.Spec.supervisor/3 and Supervisor.Spec.worker/3 are deprecated and should be avoided; one should use child specs instead. Supervisor is not meant to receive user callbacks. The only
TAG : elixir
Date : October 03 2020, 06:00 AM , By : user6059177
How to Change Debug Color(s) of Ecto
How to Change Debug Color(s) of Ecto
hop of those help? Unfortunately, this does not seem to be possible because the color is hardcoded in Ecto.
TAG : elixir
Date : October 03 2020, 01:00 AM , By : Nguyễn Hùng
logger error when using ejabberd embedded in Elixir app
logger error when using ejabberd embedded in Elixir app
help you fix your problem You probably should downgrade your elixir version. For instance, in v1.0 there was undocumented function Logger.Config.__data__/0 that was later removed, but ejabberd for some reason relied on its existence.I have no idea wh
TAG : elixir
Date : October 02 2020, 05:00 PM , By : zhengqiang
Using Flow to Generate Sum of First 100000 / 1 Million Fibonacci terms in elixir
Using Flow to Generate Sum of First 100000 / 1 Million Fibonacci terms in elixir
will be helpful for those in need The issue is you are overcomplicating the task, blowing up the memory. What is asked? To get a sum. Has it asked to get the list of numbers? Nope. So far, so good.You do not need recursions, streams, flows, folding a
TAG : elixir
Date : October 02 2020, 05:00 AM , By : Jacob G Greenburg
function def conflicts by adding optional parameter elixir
function def conflicts by adding optional parameter elixir
Does that help , def hello/1 conflicts with defaults from hello/2
TAG : elixir
Date : October 01 2020, 02:00 PM , By : Tico Wang
Handle exception raised in task
Handle exception raised in task
To fix this issue Task is started as a separated process. The intercommunication of two processes can only be exchanging messages. One cannot expect to rescue anything happened in one process from another process—processes are isolated.One might resc
TAG : elixir
Date : October 01 2020, 03:00 AM , By : Ferrybig-bot
mix deps.get fails, {:failed_connect, [{:to_address, {'repo.hex.pm', 443}}, {:inet, [:inet], {:option, :server_only, :ho
mix deps.get fails, {:failed_connect, [{:to_address, {'repo.hex.pm', 443}}, {:inet, [:inet], {:option, :server_only, :ho
around this issue I faced the same error, for me the suggestion from @legoscia worked: update Hex with mix local.hex
TAG : elixir
Date : October 01 2020, 02:00 AM , By : DisplayName=
How can I list all of my aliases in `iex`?
How can I list all of my aliases in `iex`?
wish help you to fix your issue Sometimes I forget what I've previously aliased via alias in an iex session. , Run __ENV__.aliases:
TAG : elixir
Date : September 29 2020, 11:00 AM , By : priya m
Order by virtual computed field
Order by virtual computed field
it helps some times Thiago Henrique already answered why virtual doesn't work here, but depending on your underlying database, I would like to present another solution: Generated ColumnsGenerated Columns are available in PostgreSQL since version 12 a
TAG : elixir
Date : September 28 2020, 03:00 PM , By : ssjohn311
Phoenix 1.4: How can I keep a DBConnection across multiple requests?
Phoenix 1.4: How can I keep a DBConnection across multiple requests?
this will help Normally in a setup like this, the 1000 processes will share 100 DBConnection in the pool [...]
TAG : elixir
Date : September 27 2020, 05:00 AM , By : Harshit John
Ecto ILIKE for multiple keywords?
Ecto ILIKE for multiple keywords?
With these it helps Well, this is possible to some extent with a bit of metaprogramming. Luckily enough, ecto allows your own macros in the queries, so all we need would be to build our own macro, gluing several ILIKEs with ors.There are several pitf
TAG : elixir
Date : September 26 2020, 08:00 PM , By : Megan Nelson
Phoenix + ExUnit: where should I define global helpers?
Phoenix + ExUnit: where should I define global helpers?
I wish this helpful for you If this is just a matter of a single helper, put it into your test/test_helper.exs.But as the project grows, it becomes harder to manage. The common approach is to create test/support folder, and modify your mix.exs in the
TAG : elixir
Date : September 26 2020, 06:00 PM , By : haha
mix test does not insert data?
mix test does not insert data?
help you fix your problem Your repo is set to Sandbox mode. This means that after transaction ends (wrapped unit test) it will rollback transaction for you. Often this configuration is in test.exs file but also can be set in test/test_helper.exs
TAG : elixir
Date : September 26 2020, 03:00 PM , By : Chris Lu
How to retrieve all of the loaded modules in `iex`?
How to retrieve all of the loaded modules in `iex`?
wish helps you I wanted to know if there was a standard NotImplementedError I could pass to Kernel.raise/1. I was curious whether I could figure out (beyond just trying it) whether that module existed. , Answering the question stated
TAG : elixir
Date : September 26 2020, 03:00 PM , By : Raidy Lei
Is there an idom for building a map with the same keys and values as variables?
Is there an idom for building a map with the same keys and values as variables?
To fix the issue you can do The best way is explicitly declaring the map exactly how you want it. However, if you absolutely want a shorthand (I wouldn't recommend this), you can accomplish it with a macro:
TAG : elixir
Date : September 26 2020, 03:00 PM , By : The Dev'Meister
Why Elixir operator "in" will not work in for loops?
Why Elixir operator "in" will not work in for loops?
I wish this helpful for you Because in operator has different semantic. in is for checking whether value is in range/list. It is similar to Enum.member?/2. On the other hand
TAG : elixir
Date : September 26 2020, 06:00 AM , By : Doğuş
Elixir : Issue in defining Maps
Elixir : Issue in defining Maps
it should still fix some issue Use IO.inspect(roman_table).IO.puts requires the argument to be either a string, or anything that implements the String.Chars protocol while IO.inspect can print an arbitrary elixir term.
TAG : elixir
Date : September 25 2020, 08:00 PM , By : Skywalker5
Wrap elixir module
Wrap elixir module
seems to work fine AFAIU you want to perform some kind of object-oriented programming by replicating the logic of inheritance between classes. But this is not the philosophy of any functional programming language like Elixir as you probably already k
TAG : elixir
Date : September 24 2020, 06:00 PM , By : ahua
How to handle POST and GET requests in Elixir?
How to handle POST and GET requests in Elixir?
wish of those help With HTTPoison (HTTP Client) and Poison (JSON Encoder/Decoder) packages, this is almost as simple as your code which uses HTTParty:
TAG : elixir
Date : September 24 2020, 04:00 AM , By : Oleksandra Kosenko
Combine two columns and search on them
Combine two columns and search on them
help you fix your problem The [arguably] more common approach in such a case would be to use Ecto.Query.or_where/3
TAG : elixir
Date : September 22 2020, 09:00 AM , By : green lee
How to add information to ExUnit's output for failing tests
How to add information to ExUnit's output for failing tests
Hope this helps One way to do that is to use the message parameter of assert and friends. The message will only be shown when the assertion fails.
TAG : elixir
Date : September 20 2020, 08:00 AM , By : Karen H
How can i get the conn struct after Phoenix controller action
How can i get the conn struct after Phoenix controller action
this will help I want to send some conn info to my Elasticsearch after all controller actions of my project, example: The controller action response, the request params and the endpoint. , I got it creating a plug in my application:
TAG : elixir
Date : September 17 2020, 03:00 AM , By : J.Raney
Elixir Ecto query - preserving order of output
Elixir Ecto query - preserving order of output
will be helpful for those in need Here's my attempt at converting one of the answers from @zwippie's comment to Ecto (for Postgres):
TAG : elixir
Date : August 26 2020, 11:00 PM , By : Jacqueline Eells
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