[Tutor] Fwd: find second occurance of string in line

[Peter Otten]

richard kappler wrote:

>> Do you want to find just the second occurence in the *file* or the second
> occurence within a given tag in the file (and there could be multiple such
> tags)?
> 
> There are multiple objectdata lines in the file and I wish to find the
> second occurence of timestamp in each of those lines.
> 
>> Is objectdata within a specific tag? Usually when parsing XML its the
> tags you look for first since "lines" can be broken over multiple lines
> and multiple tags can exist on one literal line.
> 
> objectdata is within a tag as is timestamp. Here's an example:
> 
> <objectdata xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
> xsi:noNamespaceSchemaLocation="Logging.xsd"
> version="1.0"><devicename>0381UDI1</devicename><deviceid>32
> </deviceid><timestamp>2015-06-18T14:28:06.570</timestamp>
> <incr>53163</incr><tokenid>0381UDI12015-06-18T14:27:50379</tokenid>
> <seqnb>1306</seqnb><general> oi="607360" on="379" ox="02503" oc="0" 
is="49787" ie="50312" lftf="N"
> lfts="7" errornb="0"
> iostate="DC00"><timestamp>2015-06-18T14:27:50.811</timestamp><otl
> unit="inch"><value>51.45</value></otl><tt
> unit="ms"><value>0</value></tt><oga

[snip]

I'm inferring from the above that you do not really want the "second" 
timestamp in the line -- there is no line left intace anyway;) -- but rather 
the one in the <general>...</general> part.

Here's a way to get these (all of them) with lxml:

import lxml.etree

tree = lxml.etree.parse("example.xml")
print tree.xpath("//objectdata/general/timestamp/text()")