一元+的错误操作数类型：“str”

Question

我想不出用Python2.7编写的代码有什么问题。我正在将引用转换为int，但是我一直得到一个类型异常bad operand type for unary +: 'str'。有人能帮忙吗？

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)

当操作数异常到达if int(splitLine[0]) > int(lastUnix):时，我正在命中操作数异常bad operand type for unary +: 'str'，即使两个被比较的值在测试时都打印为int。有人能给我一些反馈吗？谢谢您！

以下是异常响应：

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

代码对我有效。（在添加缺少的except子句/import语句之后）

你把\放进原始代码了吗？

urlToVisit = 'http://chartapi.finance.yahoo.com/instrument/1.0/' \
              + stock + '/chartdata;type=quote;range=5d/csv'

如果省略，则可能是异常的原因：

>>> stock = 'GOOG'
>>> urlToVisit = 'http://chartapi.finance.yahoo.com/instrument/1.0/'
>>> + stock + '/chartdata;type=quote;range=5d/csv'
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
TypeError: bad operand type for unary +: 'str'

顺便说一下，string(e)应该是str(e)。

Answer 2

你说是if int(splitLine[0]) > int(lastUnix):引起了麻烦，但实际上你没有表现出任何暗示。 我认为这一行是问题所在：

print 'Pulled', + stock

你明白为什么这一行会导致错误信息吗？你也要

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

或者

>>> 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'

你要求Python将+符号应用于一个字符串，比如+23使23为正，而她反对。