code: def frombcolz(source, expression=None, outcols=None, limit=None, skip=0):
      
  
      return BcolzView(source, expression=expression, outcols=outcols,
                       limit=limit, skip=skip)
docs: Extract a table from a bcolz ctable, e.g.::
  
          >>> import petl as etl
          >>> import bcolz
          >>> cols = [
          ...     ['apples', 'oranges', 'pears'],
          ...     [1, 3, 7],
          ...     [2.5, 4.4, .1]
          ... ]
          >>> names = ('foo', 'bar', 'baz')
          >>> ctbl = bcolz.ctable(cols, names=names)
          >>> tbl = etl.frombcolz(ctbl)
          >>> tbl
          +-----------+-----+-----+
          | foo       | bar | baz |
          +===========+=====+=====+
          | 'apples'  |   1 | 2.5 |
          +-----------+-----+-----+
          | 'oranges' |   3 | 4.4 |
          +-----------+-----+-----+
          | 'pears'   |   7 | 0.1 |
          +-----------+-----+-----+
  
      If `expression` is provided it will be executed by bcolz and only
      matching rows returned, e.g.::
  
          >>> tbl2 = etl.frombcolz(ctbl, expression='bar > 1')
          >>> tbl2
          +-----------+-----+-----+
          | foo       | bar | baz |
          +===========+=====+=====+
          | 'oranges' |   3 | 4.4 |
          +-----------+-----+-----+
          | 'pears'   |   7 | 0.1 |
          +-----------+-----+-----+
  
      .. versionadded:: 1.1.0