argv[0] and __file__ inconsistency
I currently use ActivePython 2.5.1. Consider the following code which I saved as cmdline.py: import sys print sys.argv[0] If I invoke this code as 'python cmdline.py', then the output is: cmdline.py If I invoke it as 'cmdline.py', then the output is: C:\Users\hai\src\python\cmdline.py The same happens for __file__. My question: do you have any suggestions for a more consistent way to figure out the full path of your script? -- http://mail.python.org/mailman/listinfo/python-list
Re: argv[0] and __file__ inconsistency
> use os.path.abspath Bingo! This is just what the doctor ordered. Thank you. Hai -- http://mail.python.org/mailman/listinfo/python-list
Re: Parsing links within a html file.
On Jan 14, 9:59 am, Shriphani <[EMAIL PROTECTED]> wrote: > Hello, > I have a html file over here by the name guide_ind.html and it > contains links to other html files like guides.html#outline . How do I > point BeautifulSoup (I want to use this module) to > guides.html#outline ? > Thanks > Shriphani P. Try Mark Pilgrim's excellent example at: http://www.diveintopython.org/http_web_services/index.html >From the above link, you can retrieve openanything.py which I use in my example: # list_url.py # created by Hai Vu on 1/16/2008 from openanything import fetch from sgmllib import SGMLParser class RetrieveURLs(SGMLParser): def reset(self): SGMLParser.reset(self) self.urls = [] def start_a(self, attributes): url = [v for k, v in attributes if k.lower() == 'href'] self.urls.extend(url) print '\t%s' % (url) # -- # main def main(): site = 'http://www.google.com' result = fetch(site) if result['status'] == 200: # Extracts a list of URLs off the top page parser = RetrieveURLs() parser.feed(result['data']) parser.close() # Display the URLs we just retrieved print '\nURL retrieved from %s' % (site) print '\t' + '\n\t'.join(parser.urls) else: print 'Error (%d) retrieving %s' % (result['status'], site) if __name__ == '__main__': main() -- http://mail.python.org/mailman/listinfo/python-list
Re: reading a specific column from file
Here is another suggestion:
col = 2 # third column
filename = '4columns.txt'
third_column = [line[:-1].split('\t')[col] for line in open(filename,
'r')]
third_column now contains a list of items in the third column.
This solution is great for small files (up to a couple of thousand of
lines). For larger file, performance could be a problem, so you might
need a different solution.
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Re: "Code Friendly" Blog?
On Jan 17, 2:50 pm, Miki <[EMAIL PROTECTED]> wrote: > Hello, > > Posting code examples to blogger.com hosted blog is not fun (need to > remember alway escape < and >). > Is there any free blog hosting that is more "code friendly" (easy to > post code snippets and such)? > > Thanks, > -- > Miki <[EMAIL PROTECTED]>http://pythonwise.blogspot.com how about bracketing your code in the tags? Something like this: import sys, os, shutil def getDir(fullPath): dirName, fileName = os.path.split(fullPath) return dirName -- http://mail.python.org/mailman/listinfo/python-list
Re: "Code Friendly" Blog?
Miki, Why don't you try to use Code Colorizer: http://www.chamisplace.com/colorizer/cc.asp -- http://mail.python.org/mailman/listinfo/python-list
Re: Creating variables from dicts
On Feb 23, 12:53 pm, vsoler wrote:
> Hi,
>
> I have two dicts
>
> n={'a', 'm', 'p'}
> v={1,3,7}
>
> and I'd like to have
>
> a=1
> m=3
> p=7
>
> that is, creating some variables.
>
> How can I do this?
I think you meant to use the square brackets [ ] instead of the curly
ones { } to define the list:
>>> n = ['a', 'b', 'c']
>>> v = [3, 5, 7]
>>> for x, y in zip(n, v):
... exec '%s=%d' % (x, y)
...
>>> a
3
>>> b
5
>>> c
7
---
The key is the use of the exec statement, which executes the strings
"a=3", "b=5", ... as if they are python statements.
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Re: stripping fields from xml file into a csv
On Feb 27, 12:50 pm, Hal Styli wrote: > Hello, > > Can someone please help. > I have a sed solution to the problems below but would like to rewrite > in python... > > I need to strip out some data from a quirky xml file into a csv: > > from something like this > > < . cust="dick" product="eggs" ... quantity="12" > > < cust="tom" product="milk" ... quantity="2" ...> > < cust="harry" product="bread" ... quantity="1" ...> > < cust="tom" product="eggs" ... quantity="6" ...> > < . cust="dick" product="eggs" ... quantity="6" > > > to this > > dick,eggs,12 > tom,milk,2 > harry,bread,1 > tom,eggs,6 > dick,eggs,6 > > I am new to python and xml and it would be great to see some slick > ways of achieving the above by using python's XML capabilities to > parse the original file or python's regex to achive what I did using > sed. > > Thanks for any constructive help given. > > Hal Here is a sample XML file (I named it data.xml): -- -- Code: -- import csv import xml.sax # Handle the XML file with the following structure: # #... # class OrdersHandler(xml.sax.handler.ContentHandler): def __init__(self, csvfile): # Open a csv file for output self.csvWriter = csv.writer(open(csvfile, 'w')) def startElement(self, name, attributes): # Only process the element if name == 'order': # Construct a sorted list of attribute names in order to # guarantee rows are written in the same order. We assume # the XML elements contain the same attributes attributeNames = attributes.getNames() attributeNames.sort() # Construct a row and write it to the csv file row = [] for name in attributeNames: row.append(attributes.getValue(name)) self.csvWriter.writerow(row) def endDocument(self): # Destroy the csv writer object to close the file self.csvWriter = None # Main datafile = 'data.xml' csvfile = 'data.csv' ordersHandler = OrdersHandler(csvfile) xml.sax.parse(datafile, ordersHandler) -- To solve your problem, it is easier to use SAX than DOM. Basically, use SAX to scan the XML file, if you encounter the element you like (in this case ) then you process its attributes. In this case, you sort the attributes, then write to a csv file. -- References: SAX Parser: http://docs.python.org/library/xml.sax.html SAX Content Handler: http://docs.python.org/library/xml.sax.handler.html Attributes Object: http://docs.python.org/library/xml.sax.reader.html#attributes-objects -- http://mail.python.org/mailman/listinfo/python-list
Re: stripping fields from xml file into a csv
On Feb 28, 12:05 am, Stefan Behnel wrote:
> Hal Styli, 27.02.2010 21:50:
>
> > I have a sed solution to the problems below but would like to rewrite
> > in python...
>
> Note that sed (or any other line based or text based tool) is not a
> sensible way to handle XML. If you want to read XML, use an XML parser.
> They are designed to do exactly what you want in a standard compliant way,
> and they can deal with all sorts of XML formatting and encoding, for example.
>
> > I need to strip out some data from a quirky xml file into a csv:
>
> > from something like this
>
> > < . cust="dick" product="eggs" ... quantity="12" >
> > < cust="tom" product="milk" ... quantity="2" ...>
> > < cust="harry" product="bread" ... quantity="1" ...>
> > < cust="tom" product="eggs" ... quantity="6" ...>
> > < . cust="dick" product="eggs" ... quantity="6" >
>
> As others have noted, this doesn't tell much about your XML. A more
> complete example would be helpful.
>
> > to this
>
> > dick,eggs,12
> > tom,milk,2
> > harry,bread,1
> > tom,eggs,6
> > dick,eggs,6
>
> > I am new to python and xml and it would be great to see some slick
> > ways of achieving the above by using python's XML capabilities to
> > parse the original file or python's regex to achive what I did using
> > sed.
>
> It's funny how often people still think that SAX is a good way to solve XML
> problems. Here's an untested solution that uses xml.etree.ElementTree:
>
> from xml.etree import ElementTree as ET
>
> csv_field_order = ['cust', 'product', 'quantity']
>
> clean_up_used_elements = None
> for event, element in ET.iterparse("thefile.xml", events=['start']):
> # you may want to select a specific element.tag here
>
> # format and print the CSV line to the standard output
> print(','.join(element.attrib.get(title, '')
> for title in csv_field_order))
>
> # safe some memory (in case the XML file is very large)
> if clean_up_used_elements is None:
> # this assigns the clear() method of the root (first) element
> clean_up_used_elements = element.clear
> clean_up_used_elements()
>
> You can strip everything dealing with 'clean_up_used_elements' (basically
> the last section) if your XML file is small enough to fit into memory (a
> couple of MB is usually fine).
>
> Stefan
This solution is so beautiful and elegant. Thank you. Now I am off to
learn ElementTree.
By the way, Stefan, I am using Python 2.6. Do you know the differences
between ElementTree and cElementTree?
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