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doc/json_linq_cheatsheet.EN.txt  view on Meta::CPAN

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 JSON::LINQ Cheat Sheet                                    [EN] English
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[ 1. Creating Queries ]

  use JSON::LINQ;

  # From a JSON file (top-level array)
  my $q = JSON::LINQ->FromJSON('data.json');

  # From a JSONL file (one JSON object per line, streaming)
  my $q = JSON::LINQ->FromJSONL('events.jsonl');

  # From a JSON string
  my $q = JSON::LINQ->FromJSONString('[{"id":1},{"id":2}]');

  # From an LTSV file (label:value, TAB-separated, streaming)
  my $q = JSON::LINQ->FromLTSV('data.ltsv');
  # From a CSV file (first row = header, streaming)
  my $q = JSON::LINQ->FromCSV('data.csv');
  my $q = JSON::LINQ->FromCSV('data.csv', sep => "\t");        # TSV
  my $q = JSON::LINQ->FromCSV('f.csv', headers=>[qw(a b c)]); # headerless
  my $q = JSON::LINQ->FromCSV('f.csv', headers=>[qw(a b c)],  # skip existing
                               skip_header=>1);

  # From an in-memory array
  my $q = JSON::LINQ->From(\@array);

  # Empty sequence
  my $q = JSON::LINQ->Empty();

  # Integer sequence: 1, 2, 3, 4, 5
  my $q = JSON::LINQ->Range(1, 5);

  # Repeat an element N times
  my $q = JSON::LINQ->Repeat("x", 3);

  # Note: once consumed by a terminal method, the iterator is exhausted.
  # Call FromJSON/FromJSONL/From again to re-query.

[ 2. Filtering ]

  ->Where(sub { $_[0]{status} eq '200' })
  ->Where(sub { $_[0]{score} >= 80 })
  ->Where(sub { defined $_[0]{email} && $_[0]{email} ne '' })

[ 3. Projection ]

  # Select: transform each element
  ->Select(sub { { path => $_[0]{url}, code => $_[0]{status} } })
  ->Select(sub { $_[0]{name} })

  # SelectMany: flatten nested arrays (selector must return ARRAY ref)
  ->SelectMany(sub { [ @{ $_[0]{tags} } ] })

[ 4. Sorting ]

  # Primary key -- smart (numeric if both look like numbers)
  ->OrderBy(sub { $_[0]{name} })
  ->OrderByDescending(sub { $_[0]{score} })

  # Primary key -- force numeric comparison
  ->OrderByNum(sub { $_[0]{price} })
  ->OrderByNumDescending(sub { $_[0]{amount} })

  # Primary key -- force string comparison (cmp)
  ->OrderByStr(sub { $_[0]{code} })
  ->OrderByStrDescending(sub { $_[0]{name} })

  # Secondary key (chain after OrderBy*)
  ->ThenBy(sub { $_[0]{name} })              # smart ascending
  ->ThenByDescending(sub { $_[0]{score} })   # smart descending
  ->ThenByNum(sub { $_[0]{age} })            # numeric ascending
  ->ThenByNumDescending(sub { $_[0]{age} })  # numeric descending
  ->ThenByStr(sub { $_[0]{name} })           # string ascending
  ->ThenByStrDescending(sub { $_[0]{name} }) # string descending

  # Reverse current order
  ->Reverse()