Upgrade to Pro
— share decks privately, control downloads, hide ads and more …
Speaker Deck
Features
Speaker Deck
PRO
Sign in
Sign up for free
Search
Search
Ruby Trivia
Search
Erik Berlin
October 01, 2015
Programming
2
1.1k
Ruby Trivia
Presented at the Berlin Ruby User Group (RUG::B) on October 1, 2015.
Erik Berlin
October 01, 2015
Tweet
Share
More Decks by Erik Berlin
See All by Erik Berlin
Enumerator::Lazy
sferik
1
390
Ruby Trivia 3
sferik
0
560
The Value of Being Lazy
sferik
3
590
Ruby Trivia 2
sferik
0
610
💀 Symbols
sferik
5
1.6k
Content Negotiation for REST APIs
sferik
8
820
Writing Fast Ruby
sferik
622
60k
Mutation Testing with Mutant
sferik
5
990
Other Decks in Programming
See All in Programming
Netty Chicago Java User Group 2024-04-17
sullis
0
210
PostmanでAPIの動作確認が楽になった話
h455h1
0
180
Webアプリをできるだけコードを手書きしないで作ってみる
tomokusaba
2
190
WebGLで始める コンピュータグラフィックス入門
heller77
0
330
Exploring the Implementation of “t.Run”, “t.Parallel”, and “t.Cleanup”
akarin
1
140
Goのエラースタックトレースの歴史と今後
sonatard
10
1.8k
障害対応を起点としたもっといい開発と運用のサイクル作りのためにできること / Hatena Enginner Seminar #29
polamjag
0
400
Domain-Driven Transformation
hschwentner
2
1.5k
敵対的ポイフル
futabato
0
140
PHPはいつから死んでいるかの調査
chiroruxx
2
420
Try creating your own orderedmap
kazamori
1
250
Ruby GitHub Packages
bkuhlmann
0
650
Featured
See All Featured
Why You Should Never Use an ORM
jnunemaker
PRO
51
8.7k
Embracing the Ebb and Flow
colly
80
4.2k
GraphQLの誤解/rethinking-graphql
sonatard
56
9.3k
Six Lessons from altMBA
skipperchong
22
3k
For a Future-Friendly Web
brad_frost
172
9k
What's new in Ruby 2.0
geeforr
337
31k
Keith and Marios Guide to Fast Websites
keithpitt
408
22k
ParisWeb 2013: Learning to Love: Crash Course in Emotional UX Design
dotmariusz
104
6.6k
A Modern Web Designer's Workflow
chriscoyier
689
190k
Fontdeck: Realign not Redesign
paulrobertlloyd
76
4.9k
Optimising Largest Contentful Paint
csswizardry
13
2.4k
Building Your Own Lightsaber
phodgson
100
5.7k
Transcript
Ruby Trivia
In Ruby, a dash may not be used in a
variable name… …but before Ruby 2.1, one variable was allowed to be named with a dash. What was it called? Question 1:
In Ruby, a dash may not be used in a
variable name… …but before Ruby 2.1, one variable was allowed to be named with a dash. What was it called? Hint: It’s a global variable. Question 1:
$- Answer 1:
Why can’t variable names contain dashes? Bonus Question:
Why can’t variable names contain dashes? Bonus Question: Answer: Because
the Ruby parser can’t distinguish it from the minus (-) operator between two variables (e.g. forty-two).
Ruby may define a special File object in the first
file it interprets. What is it called? What does it do? Question 2:
Ruby may define a special File object in the first
file it interprets. What is it called? Question 2: Hint: When you call read, it reads the file, starting after __END__
DATA Answer 2:
What happens if you call: DATA.rewind before DATA.read Bonus Question:
What happens if you call: DATA.rewind before DATA.read Bonus Question:
Answer: It reads the entire file, including the source code.
The following line of code is valid Ruby syntax: a
= true && return But this line of code is not: a = return && true What is the error message? Question 3:
void value expression Answer 3:
When you convert the range: (1..3).to_a You get the array:
[1, 2, 3] What is the result of: (3..1).to_a Question 4:
[] Answer 4:
What method would need to be added to the Range
interface to make descending sequences possible? Bonus Question:
What method would need to be added to the Range
interface to make descending sequences possible? Bonus Question: Answer: pred (the opposite of succ).
What Ruby class mixes-in Comparable but doesn’t define the spaceship
(<=>) operator? Question 5:
What Ruby class mixes-in Comparable but doesn’t define the spaceship
(<=>) operator? Hint: It’s a descendant of Numeric. Question 5:
Complex Answer 5:
Thanks for playing! Follow @sferik on Twitter for more Ruby
trivia and practica.