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Benjamin Bernard > App-RecordStream-3.7.2 > recs-flatten


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recs-flatten --help-all ^

 Help from: --help-basic:
 Usage: recs-flatten <args> [<files>]
    Flatten nested structues 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.
    --<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
       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]}}
       recs-flatten --deep x
    We see
       {"x" => {"y" => [{"z" = "v"}]}} becomes {"x-y-0-z" => "v"}
 Help from: --help-keygroups:
    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:
    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:
    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
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