How does the SAX parser process characters?

Question

I wrote a little code to parse a XML file, and want to print it's characters, but each character seems invoke characters() callback function three times.

code：

def characters(self,chrs):
            if self.flag==1:
                    self.outfile.write(chrs+'\n')

xml file:

<e1>9308</e1>
<e2>865</e2>

and the output is like below, many blank lines.

9308


865

I think it should like:

9308

865

Why there are space line? and I read the doc info:

characters(self, content)

Receive notification of character data. The Parser will call this method to report each chunk of character data. SAX parsers may return all contiguous character data in a single chunk, or they may split it into several chunks; however, all of the characters in any single event must come from the same external entity so that the Locator provides useful information.

so SAX will process one character area as several fragments? and callback several times?

Answer 1

The example XML you posted is obviously not the full XML, because that would be malformed (and the SAX parser would tell you that instead of producing your output). So I'll assume that there's more to the XML than you showed us.

You need to be aware that every whitespace between any XML elements is character data. So if you have something like that:

<foo>
  <bar>123</bar>
</foo>

Then you have at least 3 text nodes: one containing "\n " (i.e. one newline, two space characters), one containing "123" and last but not least another one with "\n" (i.e. just a newline).