了解交互式代理Python API中的线程

Question

我阅读了一些关于Python线程的教程，以更好地理解Interactive Brokers API。但我仍然不明白为什么下面的代码不起作用：

from ibapi.client import EClient
from ibapi.wrapper import EWrapper
from ibapi.contract import Contract
from ibapi.ticktype import TickTypeEnum
import time
import threading

class TestApp(EWrapper, EClient):
def __init__(self):
EClient.__init__(self, self)
self.last_price_list = []
def error(self, reqId, errorCode, errorString):
print("Error: ", reqId, " ", errorCode, " ", errorString)
def tickPrice(self, reqId, tickType, price, attrib):
self.last_price_list = self.last_price_list + [price]
print("Tick Price. Ticker Id:", reqId, "tickType:", TickTypeEnum.to_str(tickType), "Price:", price, end=' ')
print("_______________________")



app = TestApp()

app.connect("127.0.0.1", 4002, 0)

# allow time to connect to server
time.sleep(1)

contract = Contract()
contract.symbol = "AAPL"
contract.secType = "STK"
contract.exchange = "SMART"
contract.currency = "USD"
contract.primaryExchange = "NASDAQ"

app.reqMarketDataType(4)  # switch to delayed-frozen data if live is not available
app.reqMktData(1, contract, "", False, False, [])

api_thread = threading.Thread(target=app.run())
api_thread.start()

while True:
print(len(app.last_price_list))
time.sleep(2)

以下是我打断它之前它产生的内容

Error:  -1   2104   Market data farm connection is OK:usfarm
Error:  -1   2107   HMDS data farm connection is inactive but should be available upon demand.ushmds
Error:  -1   2158   Sec-def data farm connection is OK:secdefil
Error:  1   10167   Requested market data is not subscribed. Displaying delayed market data.
Tick Price. Ticker Id: 1 tickType: DELAYED_BID Price: 152.41 _______________________
Tick Price. Ticker Id: 1 tickType: DELAYED_ASK Price: 152.46 _______________________
Tick Price. Ticker Id: 1 tickType: DELAYED_LAST Price: 152.44 _______________________
Tick Price. Ticker Id: 1 tickType: DELAYED_HIGH Price: 155.04 _______________________
Tick Price. Ticker Id: 1 tickType: DELAYED_LOW Price: 152.28 _______________________
Tick Price. Ticker Id: 1 tickType: DELAYED_CLOSE Price: 154.09 _______________________
Tick Price. Ticker Id: 1 tickType: DELAYED_OPEN Price: 154.04 _______________________

我不明白为什么这行不打印任何print(len(app.last_price_list))

Answer 1

(target=app.run)运行后没有括号，应该给出被调用方法的名称，而不是实际调用它。