From: connor.james.shea@...
Date: 2020-12-06T17:18:39+00:00
Subject: [ruby-core:101265] [Ruby master Feature#15975] Add Array#pluck

Issue #15975 has been updated by connorshea (Connor Shea).


I was going to suggest the same thing because I think it's a very useful shorthand! Here's an example I run into a lot when manipulating data in my Ruby scripts.

``` ruby
# Lets say I have an array of hashes representing video games (this is pretty
# common because I write a decent amount of scripts manipulating data in Ruby).
games = [
  {
    title: "Half-Life 2",
    steam_id: 1
  },
  {
    title: "Portal",
    steam_id: 2
  },
  {
    title: "Portal 2",
    steam_id: 3
  }
]

# If I want to get the Steam IDs for all those, for example to match this
# dataset with another dataset to find overlaps, I need to use a `map` like
# this:
games.map { |game| game[:steam_id] } #=> [1, 2, 3]

# That code above doesn't really spark joy, it's pretty lengthy for something
# that should be very simple.

# What I _want_ to do is something like this, but since these are just hash
# keys, I can't:
games.map(&:steam_id) #=> undefined method `steam_id'

# The best solution would be a `#pluck` method:
games.pluck(:steam_id) #=> [1, 2, 3]

# This sparks joy!
```

Please consider adding a #pluck method on Enumerable �������������

Ideally it'd accept more than one argument to get multiple values at once, but that's not really a deal-breaker for me if we don't include it.

Maybe it could be called #pick, #each_dig, #map_keys, or something else?

----------------------------------------
Feature #15975: Add Array#pluck
https://bugs.ruby-lang.org/issues/15975#change-88945

* Author: lewispb (Lewis Buckley)
* Status: Open
* Priority: Normal
----------------------------------------
Inspired by https://github.com/rails/rails/issues/20339

While developing web applications I've often wanted to quickly extract an array of values from an array of hashes.

With an array of objects, this is possible:

```rb
irb(main):001:0> require 'ostruct'
=> true
irb(main):002:0> [OpenStruct.new(name: "Lewis")].map(&:name)
=> ["Lewis"]
```

This PR adds Array#pluck allowing this:

```rb
irb(main):001:0> [ {name: "Lewis"} ].pluck(:name)
=> ["Lewis"]
```

without this PR:

```rb
irb(main):001:0> [ {name: "Lewis"} ].map { |item| item[:name] }
=> ["Lewis"]
```

Implemented here:

https://github.com/ruby/ruby/pull/2263



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