Questions & Help>Questions

Map.get vs. Access - pros/cons?

#elixir-map
silverdr

silverdr

Map.get vs. Access - pros/cons?

The documentation says:

Keys in maps can be accessed through some of the functions in this module (such as Map.get/3 or Map.fetch/2) or through the map[] syntax provided by the Access module

Are there any pros/cons for using one over another? I mean especially in situations where the result would be the same. Also any performance / resource usage implications of using one over another?

6 comments
#elixir-map
32 3758 6

Most Liked

sergio

sergio

fetch/2will give you an error and say HEY THIS DOES NOT EXIST. Do something about it!

Map.fetch(medical_kit, :insulin_shot)
:error # CALL 911!

Map.get/2 is more chill and will be like hey uh I couldn’t find anything here’s nil - or give you a default. Like asking your wife for your Tom Ford sunglasses and honey if you can’t find it just grab me my Raybans no big deal.

Map.get(dresser, :tom_ford_sunglasses, :raybans)

10
Post #2
marcandre

marcandre

Except map_or_kw[:something] || ”bananas" will behave differently on %{something: false} for example.

9
Post #7
BartOtten

BartOtten

Additionally, the Access syntax is also supported by Keyword List; so it allows for switching between Map en Keyword List without replacing calls.

4
Post #3

Where Next?

View thread on forum (has 6 responses!)
elixir-map
Home Questions & Help>Questions
#elixir-map
32 3761 6
Last post

Popular in Questions Top

_russellb
Questions & Help>Questions

Web scraping tools
I want to try my hand at web scraping. What tools/libraries do I need to use. I’m hoping to turn this into something professional so don’...
#web-scraping
123 19532 45
New
mcarvalho
Questions & Help>Questions

System.get_env vs. Application.get_env
What is the difference between System.get_env and Application.get_env? For example, what are best practices to use one versus another.
#environment
13 17200 6
New
skosch
Questions & Help>Questions

Put/update deep inside nested maps (and auto-create intermediate keys)
To my knowledge, put_in, Map.update etc. all have the one limitation of not automatically creating intermediate keys when needed (for exa...
#data-structures#maps#immutability
52 20278 11
New
greenz1
Questions & Help>Questions

Best way to send multiple files as HTTP response
I have a phoenix application from which a user can download multiple(5-6) files of size 1MB. I couldn’t find anything related to sending ...
/phoenix#api
3 18924 3
New
earth10
Questions & Help>Questions

Understanding Elixir/Phoenix performance
Hi, I’m just starting to build a side-project with Elixir and Phoenix and doing some basic test with Elixir alone. What strikes me is th...
/phoenix#performance#concurrency#raw-speed
222 19344 43
New
JorisKok
Questions & Help>Questions

How is it possible to get 2 million websocket connections when you have 65536 available ports?
I have a server on AWS, and was running a load test using artillery. When looking at the Phoenix dashboard I see the Ports going to 100% ...
/phoenix
20 18548 4
New
stefanchrobot
Questions & Help>Questions

How to decode a JSON into a struct safely?
What’s the safe way to decode a JSON string into a struct? I want to avoid calling String.to_atom. Jason.decode can give me a map with st...
#structs#json
29 21152 26
New
lucidguppy
Questions & Help>Questions

How do I read a file and enumerate its lines
I have a super simple question about elixir - how would I take a file like this foo bar baz and output a new file that enumerates th...
#how-to-question
20 15721 3
New
freewebwithme
Questions & Help>Questions

Failed to run 'elixir' command error in vs code
Using vs code and installed ElixirLS: support and debugger. And I got an error popped up on start up says Failed to run ‘elixir’ comma...
#vscode#elixir-ls
49 16580 39
New
joaquinalcerro
Questions & Help>Questions

What is the best approach for fetching large amount of records from postgresql with ecto
Hi there, I am working with Ecto-Postgresql and I need to call all of the records from a specific table but the table has 40,000 records...
#ecto
126 24824 27
New

Other popular topics Top

danschultzer
News>Announcing

Pow - Robust, modular, extendable user authentication and management system
None of the current solutions worked well for me, so I went ahead and built a user management system from scratch. This project took far...
/phoenix#authentication#library#authorization#user_system#pow
548 29377 241
New
siddhant3030
Questions & Help>Questions

How can I write a raw sql query?
Hi, I have to write a raw query for one of my project. But till now I have used ecto queries and don’t have much experience writing raw ...
/phoenix#ecto
13 19654 20
New
lastday4you
Questions & Help>Questions

How to check Elixir version
I wanted to check elixir version in phoenix because i found that my elixir is 1.5 but when i use Enum.chunk_by it said the function is un...
#how-to-question
11 18838 3
New
shahryarjb
Questions & Help>Questions

How to convert map to string (separated with ,)
Hello, I have map which I want to convert it to string like this: the map: %{last_name: "tavakkoli", name: "shahryar"} the string I ne...
#maps#strings
15 15660 2
New
minhajuddin
Questions & Help>Questions

Using List.first instead of Enum.at(0)
I have seen a lot of code which picks the first element from a list using Enum.at(0) instead of List.first. Is there a reason why people ...
#code-style
76 33670 14
New
joeerl
Questions & Help>Questions

Upgrading Elixir - how to check versions, delete, and upgrade?
Hello again - after a longish gap I’ve decided I really must dig into Elixir and see what’s been happening here - so I have a few questio...
#upgrade
63 41557 13
New
grych
News>Announcing

Drab: remote controlled frontend framework for Phoenix
Hi folks, Few months ago I have announced the proof-of-concept of the library to manipulate the browsers DOM objects directly from Elixi...
/phoenix#web-frameworks#library#frontend#javascript#drab
639 52341 488
New
fayddelight
Questions & Help>Questions

Installing elixir via asdf shows zsh: command not found: iex
I tried installing elixir 1.11.2 erlang 23.3.4 via asdf in my zsh shell. Enabled the versions locally and globally. When I list them ...
#erlang#asdf
44 16948 17
New
nobody
Questions & Help>Questions

How to get the server ip address?
Hi! In PHP: $_SERVER[‘SERVER_ADDR’] - in Elixir? Searched the docs for ip address and the web, no good results. Thanks!
/phoenix
19 49320 16
New
romenigld
Questions & Help>Questions

Docker run Error loading shared library libstdc++.so.6 and libgcc_s.so.1
I am trying to run a deploy with docker and I successfully runned with this command: docker build -t romenigld/blog-prod . but when I t...
/phoenix#deployment#docker-compose
30 20317 15
New
Back to top

Questions & Help>Questions

Questions Questions ❯

Latest on Elixir Forum

Elixir Forum ❯

Sponsor Spotlight

WyewWorks

Enabling companies to succeed by building software people love.

Our Sponsors

Dashbit

Build Elixir applications with speed and confidence.

EEF

Supporting innovation across the BEAM ecosystem.

Coders51

We build reliable cloud platforms for business-critical systems.

AppSignal

Catch errors, track performance, monitor hosts and more.

Honeybadger

Real-time error tracking, performance insights, and observability for devs.

Manning

Develop your skills with books, videos, and courses.

ElixirCasts

Producing high quality Elixir screencasts since 2017.

Potions

The deployment platform built for Elixir: PaaS ease, VPS control.

Pragmatic Studio

Courses that'll move you from confusion to "Aha, now I get it!"

View all our sponsors ❯

Categories:

Sub Categories:

Forums

Popular Tags

Our Sponsors

Dashbit

Build Elixir applications with speed and confidence.

EEF

Supporting innovation across the BEAM ecosystem.

Coders51

We build reliable cloud platforms for business-critical systems.

AppSignal

Catch errors, track performance, monitor hosts and more.

Honeybadger

Real-time error tracking, performance insights, and observability for devs.

Manning

Develop your skills with books, videos, and courses.

ElixirCasts

Producing high quality Elixir screencasts since 2017.

Potions

The deployment platform built for Elixir: PaaS ease, VPS control.

Pragmatic Studio

Courses that'll move you from confusion to "Aha, now I get it!"

View all our sponsors ❯

We're in Beta

About us Mission Statement