Simple tool to convert JSON array or CSV to ARFF file. Can be handy for those who use WEKA.

Using Hex, the package can be installed by adding arffy to your list of dependencies in mix.exs:

def deps do
  [
    {:arffy, "~> 0.1.0"}
  ]
end

JSON array to .arrf file: Arffy.json_to_arff("/json/path", "path/to/write/at")

[
  {
    "Id": 1,
    "Name": "Ahmad",
    "Age": 21,
    "Height": 178,
    "Tall": "NO"
  },
  {
    "Id": 2,
    "Name": "John",
    "Age": 34,
    "Height": 211,
    "Tall": "YES"
  },
  {
    "Id": 3,
    "Name": "Nathan",
    "Age": 21,
    "Height": 175,
    "Tall": "NO"
  },
  {
    "Id": 4,
    "Name": "Marco",
    "Age": 44,
    "Height": 197,
    "Tall": "YES"
  },
  {
    "Id": 5,
    "Name": "Gary",
    "Age": 18,
    "Height": 170,
    "Tall": "NO"
  }
]

@relation 'my-arffy-relation'

@attribute attr-Age numeric
@attribute attr-Height numeric
@attribute attr-Id numeric
@attribute attr-Name string
@attribute attr-Tall {NO,YES}

@data
21,178,1,Ahmad,NO
34,211,2,John,YES
21,175,3,Nathan,NO
44,197,4,Marco,YES
18,170,5,Gary,NO

CSV to .arrf file: Arffy.csv_to_arff("/csv/path", "path/to/write/at")

1,"Eldon Base for stackable storage shelf, platinum",Muhammed MacIntyre,3,-213.25,38.94,35,Nunavut,Storage & Organization,0.8
2,"1.7 Cubic Foot Compact ""Cube"" Office Refrigerators",Barry French,293,457.81,208.16,68.02,Nunavut,Appliances,0.58
3,"Cardinal Slant-DÆ Ring Binder, Heavy Gauge Vinyl",Barry French,293,46.71,8.69,2.99,Nunavut,Binders and Binder Accessories,0.39
4,R380,Clay Rozendal,483,1198.97,195.99,3.99,Nunavut,Telephones and Communication,0.58
5,Holmes HEPA Air Purifier,Carlos Soltero,515,30.94,21.78,5.94,Nunavut,Appliances,0.5
6,G.E. Longer-Life Indoor Recessed Floodlight Bulbs,Carlos Soltero,515,4.43,6.64,4.95,Nunavut,Office Furnishings,0.37
7,"Angle-D Binders with Locking Rings, Label Holders",Carl Jackson,613,-54.04,7.3,7.72,Nunavut,Binders and Binder Accessories,0.38
8,"SAFCO Mobile Desk Side File, Wire Frame",Carl Jackson,613,127.70,42.76,6.22,Nunavut,Storage & Organization,
9,"SAFCO Commercial Wire Shelving, Black",Monica Federle,643,-695.26,138.14,35,Nunavut,Storage & Organization,
10,Xerox 198,Dorothy Badders,678,-226.36,4.98,8.33,Nunavut,Paper,0.38
11,Xerox 1980,Neola Schneider,807,-166.85,4.28,6.18,Nunavut,Paper,0.4
12,Advantus Map Pennant Flags and Round Head Tacks,Neola Schneider,807,-14.33,3.95,2,Nunavut,Rubber Bands,0.53
13,Holmes HEPA Air Purifier,Carlos Daly,868,134.72,21.78,5.94,Nunavut,Appliances,0.5
14,"DS/HD IBM Formatted Diskettes, 200/Pack - Staples",Carlos Daly,868,114.46,47.98,3.61,Nunavut,Computer Peripherals,0.71
15,"Wilson Jones 1"" Hanging DublLockÆ Ring Binders",Claudia Miner,933,-4.72,5.28,2.99,Nunavut,Binders and Binder Accessories,0.37

@relation 'my-arffy-relation'

@attribute attr-0 numeric
@attribute attr-1 string
@attribute attr-2 string
@attribute attr-3 string
@attribute attr-4 numeric
@attribute attr-5 numeric
@attribute attr-6 numeric
@attribute attr-7 numeric
@attribute attr-8 string
@attribute attr-9 string
@attribute attr-10 numeric

@data
1,"Eldon Base for stackable storage shelf, platinum",Muhammed MacIntyre,3,-213.25,38.94,35,Nunavut,Storage & Organization,0.8
2,"1.7 Cubic Foot Compact ""Cube"" Office Refrigerators",Barry French,293,457.81,208.16,68.02,Nunavut,Appliances,0.58
3,"Cardinal Slant-DÆ Ring Binder, Heavy Gauge Vinyl",Barry French,293,46.71,8.69,2.99,Nunavut,Binders and Binder Accessories,0.39
4,R380,Clay Rozendal,483,1198.97,195.99,3.99,Nunavut,Telephones and Communication,0.58
5,Holmes HEPA Air Purifier,Carlos Soltero,515,30.94,21.78,5.94,Nunavut,Appliances,0.5
6,G.E. Longer-Life Indoor Recessed Floodlight Bulbs,Carlos Soltero,515,4.43,6.64,4.95,Nunavut,Office Furnishings,0.37
7,"Angle-D Binders with Locking Rings, Label Holders",Carl Jackson,613,-54.04,7.3,7.72,Nunavut,Binders and Binder Accessories,0.38
8,"SAFCO Mobile Desk Side File, Wire Frame",Carl Jackson,613,127.70,42.76,6.22,Nunavut,Storage & Organization,
9,"SAFCO Commercial Wire Shelving, Black",Monica Federle,643,-695.26,138.14,35,Nunavut,Storage & Organization,
10,Xerox 198,Dorothy Badders,678,-226.36,4.98,8.33,Nunavut,Paper,0.38
11,Xerox 1980,Neola Schneider,807,-166.85,4.28,6.18,Nunavut,Paper,0.4
12,Advantus Map Pennant Flags and Round Head Tacks,Neola Schneider,807,-14.33,3.95,2,Nunavut,Rubber Bands,0.53
13,Holmes HEPA Air Purifier,Carlos Daly,868,134.72,21.78,5.94,Nunavut,Appliances,0.5
14,"DS/HD IBM Formatted Diskettes, 200/Pack - Staples",Carlos Daly,868,114.46,47.98,3.61,Nunavut,Computer Peripherals,0.71
15,"Wilson Jones 1"" Hanging DublLockÆ Ring Binders",Claudia Miner,933,-4.72,5.28,2.99,Nunavut,Binders and Binder Accessories,0.37

Documentation can be generated with ExDoc and published on HexDocs. Once published, the docs can be found at https://hexdocs.pm/arffy.