一元+的错误操作数类型：'str'

Question

我无法弄清楚使用Python 2.7编写的代码存在的问题。我正在将引用转换为ints，但是我不断收到类型异常bad operand type for unary +: 'str'。有人可以协助吗？

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)

我遇到了操作数异常bad operand type for unary +: 'str'，if int(splitLine[0]) > int(lastUnix):即使被比较的两个值在测试时都打印为整数。谁能给我一些反馈？谢谢！

这是异常响应：

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

您说这if int(splitLine[0]) > int(lastUnix):是造成麻烦的原因，但实际上您并未显示任何暗示该问题的信息。我认为这是问题所在：

print 'Pulled', + stock

您知道为什么这一行会导致该错误消息吗？你想要

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

要么

>>> print 'Pulled ' + stock
Pulled AAAA

不

>>> 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'

您要让Python将+符号应用于像+23正23这样的字符串，而她反对。