cut and regex: why doesn't this example work?

[aborruso]

Hi,
I have the JSON input at the bottom.

If I run <input.json | mlr --j2x cut -r -f "^@g", I have

@graph.1.@id                      impresa:LgU0qvE+USpLWpu+dbQePfm7KJfG8SOgr/YdHGlu9VI=
@graph.1.@type                    impresa
@graph.1.idBene                   2030
@graph.1.mBene                    A-PA-301560
@graph.1.sBene                    A-PA-2030-S
@graph.1.iterAmministrativoAttivo DESTINATO
@graph.2.@id                      impresa:23sS3uBiY1ZUgO9zTlRswfm7KJfG8SOgr/YdHGlu9VI=
@graph.2.@type                    impresa
@graph.2.idBene                   2035
@graph.2.mBene                    A-BN-312138
@graph.2.sBene                    A-BN-2035-S
@graph.2.iterAmministrativoAttivo DESTINATO
@graph.3.@id                      impresa:Rkp64uKWWg4624pPVH0x2Q==
@graph.3.@type                    impresa
@graph.3.idBene                   2036
@graph.3.mBene                    A-BN-312139
@graph.3.sBene                    A-BN-2036-S
@graph.3.iterAmministrativoAttivo DESTINATO
@graph.4.@id                      impresa:G8GiEGax1LSanPDijSE4Jg==
@graph.4.@type                    impresa
@graph.4.idBene                   2037
@graph.4.mBene                    A-BN-312140
@graph.4.sBene                    A-BN-2037-S
@graph.4.iterAmministrativoAttivo IN GESTIONE

If I modify my regex in example in "^@graph.1" I have empty result. What's my error?

Thank you

{
  "@context": {
    "dsbase": "https://aziendeconfiscate.infocamere.it/odacWeb/",
    "impresa": "dsbase:impresa/",
    "idBene": "impresa:idBene",
    "mBene": "impresa:mBene",
    "sBene": "impresa:sBene",
    "iterAmministrativoAttivo": "tipoIterAmministrativoAttivo"
  },
  "@graph": [
    {
      "@id": "impresa:LgU0qvE+USpLWpu+dbQePfm7KJfG8SOgr/YdHGlu9VI=",
      "@type": "impresa",
      "idBene": "2030",
      "mBene": "A-PA-301560",
      "sBene": "A-PA-2030-S",
      "iterAmministrativoAttivo": "DESTINATO"
    },
    {
      "@id": "impresa:23sS3uBiY1ZUgO9zTlRswfm7KJfG8SOgr/YdHGlu9VI=",
      "@type": "impresa",
      "idBene": "2035",
      "mBene": "A-BN-312138",
      "sBene": "A-BN-2035-S",
      "iterAmministrativoAttivo": "DESTINATO"
    },
    {
      "@id": "impresa:Rkp64uKWWg4624pPVH0x2Q==",
      "@type": "impresa",
      "idBene": "2036",
      "mBene": "A-BN-312139",
      "sBene": "A-BN-2036-S",
      "iterAmministrativoAttivo": "DESTINATO"
    },
    {
      "@id": "impresa:G8GiEGax1LSanPDijSE4Jg==",
      "@type": "impresa",
      "idBene": "2037",
      "mBene": "A-BN-312140",
      "sBene": "A-BN-2037-S",
      "iterAmministrativoAttivo": "IN GESTIONE"
    }
  ]
}

[johnkerl]

@aborruso sorry for the delay!!

The confusion is because:

• On input the field name is @graph
• On output the field names (flattened) are @graph.1.@id through @graph.4.iterAmministrativoAttivo
• Flatten happens, by default, the very last step before output
• The cut operates on the input field name not the output field names

This should probably be made clearer somehow:

• mlr cut --help
• Some examples in the webdocs

As for how to do the cut you want: you can flatten before cut

mlr --from input.json --j2x flatten then cut -r -f '^@graph.1.*'
@graph.1.@id                      impresa:LgU0qvE+USpLWpu+dbQePfm7KJfG8SOgr/YdHGlu9VI=
@graph.1.@type                    impresa
@graph.1.idBene                   2030
@graph.1.mBene                    A-PA-301560
@graph.1.sBene                    A-PA-2030-S
@graph.1.iterAmministrativoAttivo DESTINATO