# Writing YAML files in Ruby: lack of pretty printing formatting options **URL:** \ **Category:** Ruby\ **Created:** [November 17, 2015, 10:36am UTC](https://www.ruby-forum.com/t/writing-yaml-files-in-ruby-lack-of-pretty-printing-formatting-options/243488 "2015-11-17T10:36:42Z")\ **Posts on this page:** 5\ **Page:** 1
**Author:** ![Sadaf\_N](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/s/858c86/32.png) [@Sadaf\_N](https://www.ruby-forum.com/u/Sadaf_N)\ **Post date:** [November 17, 2015, 10:36am UTC](https://www.ruby-forum.com/t/writing-yaml-files-in-ruby-lack-of-pretty-printing-formatting-options/243488/1 "2015-11-17T10:36:42Z")
What do you think about it ? > ---
**Author:** ![solyaris](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/s/3ec8ea/32.png) [@solyaris](https://www.ruby-forum.com/u/solyaris)\ **Post date:** [November 18, 2015, 9:43am UTC](https://www.ruby-forum.com/t/writing-yaml-files-in-ruby-lack-of-pretty-printing-formatting-options/243488/2 "2015-11-18T09:43:49Z")
Ciao Giorgio, Most YAML libraries I’ve worked with don’t preserve formatting or comments. Some quick research turns up only one that does—and it’s for Python (ruamel.yaml). In my experience, YAML is great for human-friendly, machine-readable configuration files and not much else. It loses its allure the second you bring machine-writeability into the picture. In the past, when I’ve needed to programmatically update a YAML file, I try to treat it like any other text file. That is, I’ll seek to the line(s) I want to edit, apply a regex substitution or what have you, and write out the updated file. If I have to do a lot of heavy lifting within the file and it makes more sense to manipulate the data directly, I resign myself to losing my preferred formatting, and put all of my comments in as data, i.e. instead of this: ``` # This file contains the configuration for yadda yadda yadda... # Lorem ipsum dolor sit amet, consectetur adipiscing elit. --- - apples # red - oranges # orange - bananas # yellow ... ``` I’ll do something like this: ``` --- README: | This file contains the configuration for yadda yadda yadda... Lorem ipsum dolor sit amet, consectetur adipiscing elit. ... --- - item: apples comments: red - item: oranges comments: orange - item: bananas comments: yellow ... ``` I feel like I’m giving this answer a lot lately, but if you really need a YAML library for Ruby that preserves comments and formatting, it might be fun to write! 🙂 ---
**Author:** ![solyaris](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/s/3ec8ea/32.png) [@solyaris](https://www.ruby-forum.com/u/solyaris)\ **Post date:** [November 18, 2015, 1:33pm UTC](https://www.ruby-forum.com/t/writing-yaml-files-in-ruby-lack-of-pretty-printing-formatting-options/243488/3 "2015-11-18T13:33:04Z")
Thanks for your answer, Mike You perfectly got the point with your example containings comments and pretty printed data. In facts key “comment” in my example is just to simulate a … comment as you did in your README key example. Probably you are right: I could made “Yet Another YAML” gem myself 🙂 a bit of parsing exercise (I’m not so good in parsing programming). And the reason I asked here is because I hope some one else already did a better gem 🙂 BTW, the “raugh” Ruby YAML implementation in 2016, seriously surprise me a bit, because, If I well remebers, few years ago, almost every Ruby tutorial for beginners as me, was starting with statement: YAML everywhere! YAML everywhere! YAML everywhere! (See Rails configs too, etc.) Anyway, jokes a part: Yes, YAML is not perfect, but I’m still interested in YAML as shareable format comprensible by both humans and both machines 😉 Ok otherwise we have JSON, binary mixin like superb [messagepack.org](http://messagepack.org) and of course binary blobs data at the opposite extreme 🙂 ---
**Author:** ![solyaris](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/s/3ec8ea/32.png) [@solyaris](https://www.ruby-forum.com/u/solyaris)\ **Post date:** [November 18, 2015, 7:37pm UTC](https://www.ruby-forum.com/t/writing-yaml-files-in-ruby-lack-of-pretty-printing-formatting-options/243488/4 "2015-11-18T19:37:05Z")
Sure, YAML everywhere in Rails, but only for human-friendly, machine-readable configuration. Does Rails ever write back out to YAML? ---
**Author:** ![solyaris](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/s/3ec8ea/32.png) [@solyaris](https://www.ruby-forum.com/u/solyaris)\ **Post date:** [November 19, 2015, 7:24am UTC](https://www.ruby-forum.com/t/writing-yaml-files-in-ruby-lack-of-pretty-printing-formatting-options/243488/5 "2015-11-19T07:24:51Z")
> Does Rails ever write back out to YAML? No, I agree 🙂 But this is not a good reason to do not write YAML files (I’m Rails oppositor, joking)