python - 一元操作数类型错误 + : 'str'

Question

我无法弄清楚我在使用 Python 2.7 编写的代码时遇到的问题。我正在将引用转换为整数，但我不断收到类型异常bad operand type for unary +:'str'。有人可以帮忙吗？

import urllib2
import time
import datetime

stocksToPull = 'EBAY', 'AAPL'


def pullData(stock):
    try:
        print 'Currently pulling', stock
        print str(datetime.datetime.fromtimestamp(time.time()).strftime('%Y-%m-%d %H:%M:%S'))
        urlToVisit = 'http://chartapi.finance.yahoo.com/instrument/1.0/' + \
            stock + '/chartdata;type=quote;range=3y/csv'
        saveFileLine = stock + '.txt'

        try:
            readExistingData = open(saveFileLine, 'r').read()
            splitExisting = readExistingData.split('\n')
            mostRecentLine = splitExisting[-2]
            lastUnix = mostRecentLine.split(',')[0]
        except Exception, e:
            print str(e)
            time.sleep(1)
            lastUnix = 0

        saveFile = open(saveFileLine, 'a')
        sourceCode = urllib2.urlopen(urlToVisit).read()
        splitSource = sourceCode.split('\n')

        for eachLine in splitSource:
            if 'values' not in eachLine:
                splitLine = eachLine.split(',')
                if len(splitLine) == 6:
                    if int(splitLine[0]) > int(lastUnix):
                        lineToWrite = eachLine + '\n'
                        saveFile.write(lineToWrite)
        saveFile.close()

        print 'Pulled', + stock
        print 'Sleeping....'
        print str(datetime.datetime.fromtimestamp(time.time()).strftime('%Y-%m-%d %H:%M:%S'))
        time.sleep(120)

    except Exception, e:
        print 'main loop', str(e)


for eachStock in stocksToPull:
    pullData(eachStock)

当它到达 if int(splitLine[0]) > int(lastUnix): 时，我遇到了操作数异常 bad operand type for unary +: 'str' > 即使两个被比较的值在测试时都打印为整数。谁能给我一些反馈？谢谢!

这里是异常响应:

Currently pulling EBAY
2013-12-21 11:32:40
Pulled main loop bad operand type for unary +: 'str'
Currently pulling AAPL
2013-12-21 11:32:41
Pulled main loop bad operand type for unary +: 'str'`

Answer 1

你说 if int(splitLine[0]) > int(lastUnix): 造成了麻烦，但你实际上并没有显示任何暗示这一点的东西。我认为这条线是问题所在:

print 'Pulled', + stock

你明白为什么这条线会导致错误信息吗？你想要一个

>>> stock = "AAAA"
>>> print 'Pulled', stock
Pulled AAAA

或

>>> print 'Pulled ' + stock
Pulled AAAA

不是

>>> print 'Pulled', + stock
PulledTraceback (most recent call last):
  File "<ipython-input-5-7c26bb268609>", line 1, in <module>
    print 'Pulled', + stock
TypeError: bad operand type for unary +: 'str'

您要求 Python 将 + 符号应用于像 +23 这样的字符串，得到一个正数 23，而她反对。