python - ValueError: could not convert string to float: (buffer related?) -

condensed code

# attempt condense code while preserving parts # relevant question  xml.sax import handler, make_parser  class pdoshandler(handler.contenthandler):     def __init__(self, data):         self.data   = data         self.parts  = { 'energy_values': 0 }         self.energy_values = []      def startdocument( self ):         print "reading started"      def startelement(self, name, attrs):         key, val in self.parts.iteritems():             if( name == key ):                 self.parts[key] = 1;      def characters( self, ch ):         if self.parts['energy_values'] :             if ch != '\n':                 self.data.energy_values.append(float(ch.strip()))  def pdosreader(inp, data):     handler = pdoshandler(data)     parser = make_parser()     parser.setcontenthandler(handler)     infile = open(inp)     parser.parse(infile)      infile.close() 

line 153-155:

if( self.parts['energy_values'] ):     if( ch != '\n' ):         self.data.energy_values.append( string.atof(normalize_whitespace( ch ) ) ) 

error:

traceback (most recent call last):   file "siesta_pdos.py", line 286, in <module>     main()   file "siesta_pdos.py", line 278, in main     pdosreader( args[0], data )   file "siesta_pdos.py", line 262, in pdosreader     parser.parse( infile )   file "/usr/lib/python2.7/xml/sax/expatreader.py", line 107, in parse     xmlreader.incrementalparser.parse(self, source)   file "/usr/lib/python2.7/xml/sax/xmlreader.py", line 123, in parse     self.feed(buffer)   file "/usr/lib/python2.7/xml/sax/expatreader.py", line 207, in feed     self._parser.parse(data, isfinal)   file "siesta_pdos.py", line 155, in characters     self.data.energy_values.append( string.atof(normalize_whitespace( ch ) ) )   file "/usr/lib/python2.7/string.py", line 388, in atof     return _float(s) valueerror: not convert string float: 

inputfile:

<pdos> <nspin>2</nspin> <norbitals>7748</norbitals> <energy_values>            -29.99997            -29.98997            -29.97996            ...            ... (3494 lines skipped)            ...              4.97999              4.98999              4.99999 </energy_values> </pdos> 

full input at: http://dl.dropbox.com/u/10405722/inputfile.dat

full code at: http://dl.dropbox.com/u/10405722/siesta_pdos.py

---

the code reads correctly first 3116 values , exits error. note same code shorter input (e.g. 3000 lines) works fine. therefore seems me buffer-related error has nothing atof.

any idea?

the documentation says string.atof is

deprecated since version 2.0: use float() built-in function.

you claim float() doesn't work, means input invalid. easy use print when finding out why doesn't work expect

if( ch != '\n' ):     print repr(ch), repr(ch.strip())     print repr(normalize_whitespace(ch))     print repr(float(ch.strip()))     self.data.energy_values.append(string.atof(normalize_whitespace(ch))) 

because had explain normalize_whitespace, means bad synonym; if called strip, every reader know did without having up.

in case don't know repr intended reduce ambiguity. example:

>>> x = '1.234' >>> print x 1.234 >>> print repr(x) '1.234' >>> print repr(float(x)) 1.234 

with first print, unclear whether x numeric or string. repr, there no guessing involved.