Import YAML file into Mathematica

Question

Has anyone implemented the import of YAML data files into Mathematica? I suppose some sort of transformation into a nested list of rules would be the way to do it. Thanks

There are many YAML parsers for Java, and Mathematica has J/Link. It should be possible to use those two together. — Gustavo Delfino, Sep 30 '14 at 12:46

score 6 · Answer 1 · answered Mar 23 '20 at 05:25

6

I wrote such a cross-platform tool to convert other formats to wolfram format: WolframExchange

Usage

wex in.yml      # check file but no output
wex in.yml -t   # output only text
wex in.yml -c   # output only binary
wex in.yml -ct  # output both text and binary

Result

answered Mar 23 '20 at 05:25

Aster

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This is very cool! – b3m2a1 Mar 23 '20 at 08:30

ZachB · Answer 2 · 2016-10-12T05:42:15.637

5

I just wrote an importer: https://github.com/zbjornson/MYaml. It's built on SnakeYAML and supports all language-independent types.

Example 2.10 from the spec:

In[1]:= ImportString["---
 hr:
   - Mark McGwire
   # Following node labeled SS
   - &SS Sammy Sosa
 rbi:
   - *SS # Subsequent occurrence
   - Ken Griffey", "YAML"]
Out[1]= {
          "hr" -> {"Mark McGwire", "Sammy Sosa"}, 
          "rbi" -> {"Sammy Sosa", "Ken Griffey"}
        }

More examples in the test suite.

edited Oct 12 '16 at 05:42

answered Oct 12 '16 at 03:15

ZachB

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For demonstration purposes, can you show how your importer acts on a sample YAML file? – J. M.'s missing motivation Oct 12 '16 at 03:21
@J.M. good call, added an example. – ZachB Oct 12 '16 at 05:42
1

Consider posting it on http://packagedata.net/ too – Szabolcs Oct 12 '16 at 06:41
Another importer was written just a few days ago, see at the end of comment thread here: http://mathematica.stackexchange.com/q/127300/12 – Szabolcs Oct 12 '16 at 06:43
Added to packagedata, thanks. :) – ZachB Oct 12 '16 at 17:35
I got a successful "Installed YAML importer to..." and restarted the kernel, but if I try to use it with Import or ImportString I get the error "The Import element "YAML" is not present when importing as Text". I believe this is because it's not recognizing the "YAML" as a data format and is falling back and assuming it's a specified element of the data. Anyway to troubleshoot this? – Jess Riedel Sep 05 '18 at 23:49
1

@JessRiedel You're correct. I'm not on a computer with M right now but can double check in the morning that a fresh install works. What version of M are you using? You can try manually loading this file to register the importer, something like << FileNameJoin[{$BaseDirectory, "SystemFiles", "Formats", "YAML", "Import.m"}]. – ZachB Sep 06 '18 at 02:21
Gah, it turns out I just needed to use $UserBaseDirectory instead of $BaseDirectory. The folder at $BaseDirectory doesn't actually exist on my machine, and the installation code fails silently in this case (which is totally reasonable given the audience size; I should have just checked things more carefully). Thanks much for your fast help. – Jess Riedel Sep 06 '18 at 02:48
Thanks for reporting back. I'll try to make it print a helpful error in that situation. – ZachB Sep 06 '18 at 03:59

score 2 · Answer 3 · answered Mar 03 '14 at 18:06

2

If you cannot find a YAML importer, consider converting the YAML to JSON and importing that. It'll give you the list of rules you'd expect.

answered Mar 03 '14 at 18:06

Szabolcs

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Import YAML file into Mathematica

3 Answers3

Usage

Result

Linked