PyTables + Pandas选择问题

Question

我有一个HDF5 (PyTables)文件，结构如下：

/<User>/<API Key>
ex:
/Dan/A4N5
/Dan/B8P0
/Dave/D3Y7

每个表的结构都是这样的，其中包含一个sessionID和一个以纪元存储的时间：

    sessionID        time
0   3ODE3Nzll  1467590400
1   lMGVkMDc4  1467590400
2   jNzIzNmY1  1467590400
...

我希望Pandas遍历每个表，并获取指定日期和指定日期前一天之间的所有行。目前我有这样的代码：

scriptPath = os.path.dirname(os.path.abspath(__file__))
argdate = "2016/07/14"
dayTimestamp = datetime.datetime(int(argdate[0:4]), int(argdate[5:7]), int(argdate[8:10]), tzinfo=pytz.utc)
yesterdayTimestamp = dayTimestamp - datetime.timedelta(days=1)
with pd.HDFStore(os.path.join(scriptPath, "userdatabase.h5")) as db:
    for table in db.keys():
        print(table)
        tableSplit = table.split('/')
        client = tableSplit[1]
        apiKey = tableSplit[2]
        df = db.select('{}/{}'.format(client, apiKey), where='time<=int(dayTimestamp.timestamp()) & time>=int(yesterdayTimestamp.timestamp())')
        print(df)

但是，在select所在的行上抛出错误。

  File "tester.py", line 570, in database
    df = db.select('{}/{}'.format(client, apiKey), where='time<=int(dayTimestamp.timestamp()) & time>=int(yesterdayTimestamp.timestamp())')
  File "/usr/local/lib/python3.4/dist-packages/pandas/io/pytables.py", line 680, in select
    return it.get_result()
  File "/usr/local/lib/python3.4/dist-packages/pandas/io/pytables.py", line 1364, in get_result
    results = self.func(self.start, self.stop, where)
  File "/usr/local/lib/python3.4/dist-packages/pandas/io/pytables.py", line 673, in func
    columns=columns, **kwargs)
  File "/usr/local/lib/python3.4/dist-packages/pandas/io/pytables.py", line 4021, in read
    if not self.read_axes(where=where, **kwargs):
  File "/usr/local/lib/python3.4/dist-packages/pandas/io/pytables.py", line 3222, in read_axes
    self.selection = Selection(self, where=where, **kwargs)
  File "/usr/local/lib/python3.4/dist-packages/pandas/io/pytables.py", line 4580, in __init__
    self.terms = self.generate(where)
  File "/usr/local/lib/python3.4/dist-packages/pandas/io/pytables.py", line 4593, in generate
    return Expr(where, queryables=q, encoding=self.table.encoding)
  File "/usr/local/lib/python3.4/dist-packages/pandas/computation/pytables.py", line 517, in __init__
    self.terms = self.parse()
  File "/usr/local/lib/python3.4/dist-packages/pandas/computation/expr.py", line 727, in parse
    return self._visitor.visit(self.expr)
  File "/usr/local/lib/python3.4/dist-packages/pandas/computation/expr.py", line 311, in visit
    return visitor(node, **kwargs)
  File "/usr/local/lib/python3.4/dist-packages/pandas/computation/expr.py", line 317, in visit_Module
    return self.visit(expr, **kwargs)
  File "/usr/local/lib/python3.4/dist-packages/pandas/computation/expr.py", line 311, in visit
    return visitor(node, **kwargs)
  File "/usr/local/lib/python3.4/dist-packages/pandas/computation/expr.py", line 320, in visit_Expr
    return self.visit(node.value, **kwargs)
  File "/usr/local/lib/python3.4/dist-packages/pandas/computation/expr.py", line 311, in visit
    return visitor(node, **kwargs)
  File "/usr/local/lib/python3.4/dist-packages/pandas/computation/expr.py", line 655, in visit_BoolOp
    return reduce(visitor, operands)
  File "/usr/local/lib/python3.4/dist-packages/pandas/computation/expr.py", line 647, in visitor
    lhs = self._try_visit_binop(x)
  File "/usr/local/lib/python3.4/dist-packages/pandas/computation/expr.py", line 643, in _try_visit_binop
    return self.visit(bop)
  File "/usr/local/lib/python3.4/dist-packages/pandas/computation/expr.py", line 311, in visit
    return visitor(node, **kwargs)
  File "/usr/local/lib/python3.4/dist-packages/pandas/computation/expr.py", line 628, in visit_Compare
    return self.visit(binop)
  File "/usr/local/lib/python3.4/dist-packages/pandas/computation/expr.py", line 311, in visit
    return visitor(node, **kwargs)
  File "/usr/local/lib/python3.4/dist-packages/pandas/computation/expr.py", line 401, in visit_BinOp
    op, op_class, left, right = self._possibly_transform_eq_ne(node)
  File "/usr/local/lib/python3.4/dist-packages/pandas/computation/expr.py", line 354, in _possibly_transform_eq_ne
    right = self.visit(node.right, side='right')
  File "/usr/local/lib/python3.4/dist-packages/pandas/computation/expr.py", line 311, in visit
    return visitor(node, **kwargs)
  File "/usr/local/lib/python3.4/dist-packages/pandas/computation/expr.py", line 615, in visit_Call_legacy
    return self.const_type(res(*args, **keywords), self.env)
TypeError: 'str' object is not callable

1)如何修复此错误？

2)是否可以遍历HDF5文件层次结构，以便对相同的Pandas表进行分组？