我有以下数据框，但很难访问特定的行。
我尝试使用.string与日期字符串，但是由于某种原因，要弄清楚这一点确实很困难。
如何按日期访问特定记录？
close high low open volume \
symbol time
SPY 2017-01-12 216.549143 216.558680 215.147191 215.881547 48079858.0
2017-01-13 216.081825 216.253493 214.546354 216.015066 47029340.0
2017-01-14 216.520532 216.873404 216.196271 216.234419 33441289.0
2017-01-18 215.814787 216.282104 215.347470 215.833861 34874542.0
2017-01-19 216.243956 216.301179 215.442841 216.053214 33340515.0
2017-01-20 215.490526 216.491920 214.975523 216.339327 37762597.0
2017-01-21 216.205808 216.787570 215.585897 216.205808 58009364.0
print(data.index)
MultiIndex(levels=[['SPY'], [2017-01-12 00:00:00, 2017-01-13 00:00:00, 2017-01-14 00:00:00, 2017-01-18 00:00:00, 2017-01-19 00:00:00, 2017-01-20 00:00:00, 2017-01-21 00:00:00]],
labels=[[0, 0, 0, 0, 0, 0, 0], [0, 1, 2, 3, 4, 5, 6]],
names=['symbol', 'time'])