pandas - 将 KDB 查询返回到 pandas 数据框

Question

我想从 KDB 数据库中提取数据并放入数据框中。我的查询在 qpad 中运行良好，没有问题；只需要将它写入我的 Pandas 数据框中。我的代码：

from qpython import qconnection

# Create the connection and save the handle to a variable
q  = qconnection.QConnection(host = 'wokplpaxvj003', port = 11503, username = 'pelucas', password = 'Dive2600', timeout = 3.0)
try:
    # initialize connection
    q.open()
    print(q)
    print('IPC version: %s. Is connected: %s' % (q.protocol_version, q.is_connected()))

    df = q.sendSync('{select from quote_flat where date within (2019.08.14;2019.08.14), amendment_no = (max;amendment_no)fby quote_id}')

    df.info()

finally:
    q.close()

df.info()它在加注时失败了，AttributeError: 'QLambda' object has no attribute 'info'所以我猜跟注不成功。

Answer 1

看起来您只发送了一个 lambda，但没有执行该 lambda 的指令。两种选择：

1. 不要让它成为 lambda

df = q.sendSync('select from quote_flat where date within (2019.08.14;2019.08.14), amendment_no = (max;amendment_no)fby quote_id')

2. 执行 lambda

df = q.sendSync('{select from quote_flat where date within (2019.08.14;2019.08.14), amendment_no = (max;amendment_no)fby quote_id}[]')