Python - global variable is not defined (but it is)

Question

So I'm working on this file that converts a CSV to JSON, however I keep getting this error message but can't seem to figure it out. Indentation seems to be correct so I'm a bit lost on where to go with it. Code is below:

Traceback (most recent call last):

  File "/home/uwp/widgets/contentFreshness/freshmap.py", line 308, in <module>
    main()
  File "/home/uwp/widgets/contentFreshness/freshmap.py", line 303, in main
    mySite.writeJSONFile(options)
  File "/home/uwp/widgets/contentFreshness/freshmap.py", line 247, in writeJSONFile
    outputFile.write('"' + str(dateOfCrawl) + '"' )
NameError: global name 'dateOfCrawl' is not defined

Code

class Site:

    dateOfCrawl = 0;

    def __init__(self,csvFilePath):
        self.pageList = [] # ordered list of page IDs
        self.pageData={} # dictionary of individual page dictionaries, indexed on page ID
        self.titleDict = { } # dictionary of unique titles
        self.buildPageData(csvFilePath)
        self.homePageId=self.pageList[0] # only use of site.pageList
        self.depth=0

    def buildPageData(self,csvFilePath):
        global dateOfCrawl
        # read data from CSV file, build a dictionary of page data, including list of children, in order
        lines = csv.reader(open(csvFilePath, "rb"))
        for line in lines:
            pageURL=line[0]
            pageURL=re.sub('\/\Z', '',pageURL) # remove any trailing slash
            self.pageData[pageURL]={}
            self.pageData[pageURL]["URL"]=pageURL
            self.pageData[pageURL]["Title"]=self.cleanTitle(line[1],pageURL)

            # when taking the home page and chop its url the parent will be http:/
            # which should be avoided by setting it to ''
            parent = chopPath(pageURL)
            if(parent == 'http:/'):
                parent=''
                dateOfCrawl = line[2]
            self.pageData[pageURL]["Parent"]= parent
            self.pageData[pageURL]["Modified"]=line[2]
            self.pageData[pageURL]["Children"]=[] 

        list = self.pageData.keys()

        # sort IDs before attempting to match children
        self.pageList = self.pageData.keys()
        self.pageList.sort()

        lineCount = 0       
        for pageURL in self.pageList:
            # record page as child of its parent (parents must already be in the list!)
            parentURL=self.pageData[pageURL]["Parent"]

            if (lineCount > 0):
                while( self.pageData.has_key(parentURL)== False):
                    if(parentURL == ''):
                        sys.exit(pageURL + " has no parent at " + parentURL)
                    parentURL = chopPath(parentURL)
                self.pageData[parentURL]["Children"].append(pageURL)

            lineCount+=1
        self.pageCount=lineCount

    def writeJSONFile(self,options):
        global dateOfCrawl
        outputFile = options ["outputFile"]
        #see http://code.google.com/intl/en/apis/visualization/documentation/reference.html#DataTable
        outputFile.write('[')
        outputFile.write('"' + str(dateOfCrawl) + '"' )
        self.homePage.toJSON(options)
        outputFile.write(']')
        outputFile.close()

Please read http://stackoverflow.com/help/mcve and provide the full traceback. You are asking people to read though 200+ LOC to help you - help yourself first. — jonrsharpe, Oct 17 '14 at 10:22
Ah apologies, thought I had included it! I know it's a lot of code, but to get an understanding it may be necessary. — Alex6534, Oct 17 '14 at 10:23
That is **almost never the case**. Please read http://ericlippert.com/2014/03/05/how-to-debug-small-programs/, and take more time to narrow down the issue in the future. — jonrsharpe, Oct 17 '14 at 10:25
Definitely will do, again, apologies for the ignorance and I appreciate the guidance. — Alex6534, Oct 17 '14 at 10:29

score 0 · Accepted Answer · answered Oct 17 '14 at 10:33

0

You assign dateOfCrawl = 0; (please read PEP-8) as a class attribute. For some reason, you are also mixing in a global, which is completely separate. It is not really clear why dateOfCrawl should be a class (rather than instance) attribute, or why you also have the global. You should probably just:

Make it an instance attribute (move dateOfCrawl = 0 inside __init__); then
Access that in the other methods (self.dateOfCrawl).

answered Oct 17 '14 at 10:33

jonrsharpe

115,751
26
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Thank you, that solved this issue, opened a whole bunch of others but progress is progress! :). – Alex6534 Oct 20 '14 at 11:23

score 0 · Answer 2 · edited May 23 '17 at 12:11

0

You can access this variable this way:

Site.dateOfCrawl

Static class variables in Python

edited May 23 '17 at 12:11

Community

1
1

answered Oct 17 '14 at 12:31

Raznak

9
4

Aleksandar · Answer 3 · 2014-10-20T06:13:08.397

-1

You need to define global dateOfCrawl. Move dateOfCrawl = 0; inside __init__ of Site class, to be like this:

class Site:
    def __init__(self,csvFilePath):
        global dateOfCrawl
        dateOfCrawl = 0
        ....

edited Oct 20 '14 at 06:13

answered Oct 17 '14 at 10:24

Aleksandar

3,541
4
34
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Python - global variable is not defined (but it is)

3 Answers3