NAME

recs-flatten

recs-flatten --help-all

Help from: --help-basic:
Usage: recs-flatten <args> [<files>]
   Flatten nested structures in records.

   NOTE:  This script implements a strategy for dealing with nested structures
          that is almost always better handled by using keyspecs or keygroups.
          It should, in general, be as easy or easier to use those concepts with
          the data manipulations you actually want to accomplish.

Arguments:
   --<n> <fields>               For this comma-separated list of fields flatten
                                to depth n (1-9).
   --depth <nbr>                Change the default depth, negative being
                                arbitrary depth (defaults to 1).
   --key <fields>               For this comma-separated list of fields flatten
                                to the default depth (may NOT be a a key spec).
   --deep <fields>              For this comma-separated list of fields flatten
                                to arbitrary depth.
   --separator <string>         Use this string to separate joined field names
                                (defaults to "-").
   --filename-key|fk <keyspec>  Add a key with the source filename (if no
                                filename is applicable will put NONE)

  Help Options:
      --help-all        Output all help for this script
      --help            This help screen
      --help-keygroups  Help on keygroups, a way of specifying multiple keys
      --help-keys       Help on keygroups and keyspecs
      --help-keyspecs   Help on keyspecs, a way to index deeply and with regexes

    All field values may be keyspecs or keygroups, value of keyspec must not be
    an array element

Examples:
   Under
      recs-flatten -1 field
   We see
      {"field" => "value"} becomes {"field" => "value"}
      {"field" => {"subfield" => "value"}} becomes {"field-subfield" => "value"}
      {"field" => ["value1", "value2"]} becomes {"field-0" => "value1", "field-1" => "value2"}
      {"field" => {"subfield" => [0, 1]}} becomes {"field-subfield" => [0, 1]}}
   Under
      recs-flatten --deep x
   We see
      {"x" => {"y" => [{"z" = "v"}]}} becomes {"x-y-0-z" => "v"}

Help from: --help-keygroups:
KEY GROUPS
   SYNTAX: !regex!opt1!opt2... Key groups are a way of specifying multiple
   fields to a recs command with a single argument or function. They are
   generally regexes, and have several options to control what fields they
   match. By default you give a regex, and it will be matched against all first
   level keys of a record to come up with the record list. For instance, in a
   record like this:

   { 'zip': 1, 'zap': 2, 'foo': { 'bar': 3 } }

   Key group: !z! would get the keys 'zip' and 'zap'

   You can have a literal '!' in your regex, just escape it with a \.

   Normally, key groups will only match keys whose values are scalars. This can
   be changed with the 'returnrefs' or rr flag.

   With the above record !f! would match no fields, but !f!rr would match foo
   (which has a value of a hash ref)

   Options on KeyGroups:
      returnrefs, rr  - Return keys that have reference values (default:off)
      full, f         - Regex should match against full keys (recurse fully)
      depth=NUM,d=NUM - Only match keys at NUM depth (regex will match against
                        full keyspec)
      sort, s         - sort keyspecs lexically

Help from: --help-keyspecs:
  KEY SPECS
   A key spec is short way of specifying a field with prefixes or regular
   expressions, it may also be nested into hashes and arrays. Use a '/' to nest
   into a hash and a '#NUM' to index into an array (i.e. #2)

   An example is in order, take a record like this:

     {"biz":["a","b","c"],"foo":{"bar 1":1},"zap":"blah1"}
     {"biz":["a","b","c"],"foo":{"bar 1":2},"zap":"blah2"}
     {"biz":["a","b","c"],"foo":{"bar 1":3},"zap":"blah3"}

   In this case a key spec of 'foo/bar 1' would have the values 1,2, and 3 in
   the respective records.

   Similarly, 'biz/#0' would have the value of 'a' for all 3 records

   You can also prefix key specs with '@' to engage the fuzzy matching logic

   Fuzzy matching works like this in order, first key to match wins
     1. Exact match ( eq )
     2. Prefix match ( m/^/ )
     3. Match anywehre in the key (m//)

   So, in the above example '@b/#2', the 'b' portion would expand to 'biz' and 2
   would be the index into the array, so all records would have the value of 'c'

   Simiarly, @f/b would have values 1, 2, and 3

   You can escape / with a \. For example, if you have a record:
   {"foo/bar":2}

   You can address that key with foo\/bar

See Also

RecordStream(3) - Overview of the scripts and the system

recs-examples(3) - A set of simple recs examples

recs-story(3) - A humorous introduction to RecordStream

SCRIPT --help - every script has a --help option, like the output above