Reading values from xml file

2012 3 26
6 个回答
更新时间：2024 4 2
96 次查看（30 天）

0 个投票

I've read around a bit and cant seem to get this to work. I am trying to read out a specific value from stereotyped xml files. The xml files look like this: http://i.imgur.com/uSEQt.png and I am trying to access the second "Frame relativeTime" value from the file for use in a data analysis pack I'm writing. There are many "Frame realtive time" entrees in the xml file but I am just trying to pull the second value and save it as a variable."
Any thoughts?
Thanks

请先登录，再回答此问题。

回答（6 个）

7 个投票

Try
S = readstruct("abcd.xml")
it works on my matlab version.
It should work on matlab 2020b or higher version.

2 个评论
显示 无 隐藏 无

Adam Campos
Adam Campos 2022-1-18
Holy moly that just saved me hours and hours of trying to figure this stuff out. Thank you!
Hongyuan Zhang
Hongyuan Zhang 2022-2-24
This works pretty well!

请先登录，再进行评论。

Turlough Hughes
Turlough Hughes 2021-5-14

3 个投票

You can now read XML files in R2021a using readtable (and readtimetable). For example:
filename = 'students.xml';
T = readtable(filename);
You can also select specific variables or attributes to read via detectImportOptions (or XMLImportOptions) - first get the opts and display the variable names:
opts = detectImportOptions(filename);
opts.VariableNames.'
then select the variable names that you want - let's say you want FirstNameAttribute, LastNameAttribute and Age, that would go as follows:
opts.SelectedVariableNames = opts.VariableNames(2:4);
T = readtable(filename,opts)

2 个评论
显示 无 隐藏 无

Goncalo Gouveia
Goncalo Gouveia 2023-1-12
simple and easy, worked like a charm
Catherine
Catherine 2023-6-10
Agreed, this is exactly what I was looking for. I was getting nowhere with xmlread. Thank you very much.

请先登录，再进行评论。

Thomas
Thomas 2012-3-27

2 个投票

Try this from the file exchange. I have found it to be useful
http://www.mathworks.com/matlabcentral/fileexchange/28518-xml2struct
example : here is sample.xml
<?xml version="1.0"?>
<book id="bk101">
<author>Gambardella, Matthew</author>
<title>XML Developer's Guide</title>
<genre>Computer</genre>
<price>44.95</price>
<publish_date>2000-10-01</publish_date>
<description>An in-depth look at creating applications
with XML.</description>
</book>
<book id="bk102">
<author>Ralls, Kim</author>
<title>Midnight Rain</title>
<genre>Fantasy</genre>
<price>5.95</price>
<publish_date>2000-12-16</publish_date>
<description>A former architect battles corporate zombies,
an evil sorceress, and her own childhood to become queen
of the world.</description>
</book>
If I have to find the price of the second book:
c=xml2struct('sample.xml') % use function from file exchange
>> new.catalog.book{1,2}.price
ans =
Text: '5.95'

4 个评论
显示 2更早的评论 隐藏 2更早的评论

Chris
Chris 2012-3-27
Where does the ".new" come from?
new.catalog.book{1,2}.price
Chris
Chris 2012-3-27
When I enter
c=xml2struct('sample.xml')
I get c =
PVScan: [1x1 struct]
Then when I enter new.PVScan.Sequence.PVStateShard.Frame{1,1}.relativeTime i get
Undefined variable "new" or class "new.PVScan.Sequence.PVStateShard.Frame".
Thomas
Thomas 2012-3-27
sorry, it should read new=xml2struct('sample.xml')
and then new.catalog.book{1,2}.price
Chris
Chris 2012-3-27
Used your code: Still getting
Attempt to reference field of non-structure array.
Error in Calcium2Pextended>pushbutton1_Callback (line 96)
test_data.PVScan.Sequence.Frame{1,2}.Attributes.relativeTime

请先登录，再进行评论。

Image Analyst
Image Analyst 2012-3-27

1 个投票

Did you try xmlread()? Can you show your code and maybe upload your xml file and m-file somewhere so people can try something if they want to?

2 个评论
显示 无 隐藏 无

Chris
Chris 2012-3-27
I've tried xmlread(), I can get it to read the file but then I don't know how to access the relativeTime value
Image Analyst
Image Analyst 2012-3-27
Did you try it with the example code they gave? You know, all the "function theStruct = parseXML(filename)" stuff. It's complicated I know but that seems like the way they recommend in the help.

请先登录，再进行评论。

Chris
Chris 2012-3-27

0 个投票

<?xml version="1.0" encoding="utf-8"?>
<PVScan version="4.0.0.53" date="3/23/2012 12:30:30 PM" notes="">
<Lasers>
<Laser name="Pockels" index="0" />
</Lasers>
<Sequence type="TSeries Timed Element" cycle="1" xYStageGridDefined="False" xYStageGridNumXPositions="0" xYStageGridNumYPositions="0" xYStageGridOverlapPercentage="10" xYStageGridXOverlap="10" xYStageGridYOverlap="10">
<Frame relativeTime="0" absoluteTime="9.104738" index="1" label="CurrentSettings">
<File channel="1" channelName="Ch1" preAmpID="0" filename="slice1_field1_500uA_stimB(+)-001_Cycle001_CurrentSettings_Ch1_000001.tif" />
<File channel="4" channelName="Spot" preAmpID="0" filename="slice1_field1_500uA_stimB(+)-001_Cycle001_CurrentSettings_Ch4_000001.tif" />
<ExtraParameters validData="True" />
<Key key="objectiveLens" permissions="Read, Write, Save" value="10X" />
<Key key="objectiveLensNA" permissions="Read, Write, Save" value="0.3" />
<Key key="objectiveLensMag" permissions="Read, Write, Save" value="10" />
<Key key="pixelsPerLine" permissions="Read, Write, Save" value="200" />
<Key key="linesPerFrame" permissions="Read, Write, Save" value="88" />
<Key key="systemType" permissions="Write, Save" value="0" />
<Key key="binningMode" permissions="Read, Write, Save" value="0" />
<Key key="frameAveraging" permissions="Read, Write, Save" value="0" />
<Key key="framePeriod" permissions="Read, Write, Save" value="0.191488" />
<Key key="scanlinePeriod" permissions="Read, Write, Save" value="0.002176" />
<Key key="dwellTime" permissions="Read, Write, Save" value="8" />
<Key key="bitDepth" permissions="Read, Write, Save" value="12" />
<Key key="positionCurrent_XAxis" permissions="Write, Save" value="19401.38671875" />
<Key key="positionCurrent_YAxis" permissions="Write, Save" value="-20993.3203125" />
<Key key="positionCurrent_ZAxis" permissions="Write, Save" value="15902.42" />
<Key key="zDevice" permissions="Write, Save" value="0" />
<Key key="rotation" permissions="Read, Write, Save" value="20" />
<Key key="opticalZoom" permissions="Read, Write, Save" value="1" />
<Key key="micronsPerPixel_XAxis" permissions="Read, Write, Save" value="0.219298245614035" />
<Key key="micronsPerPixel_YAxis" permissions="Read, Write, Save" value="0.219298245614035" />
<Key key="pmtGain_0" permissions="Write, Save" value="786.290322580645" />
<Key key="pmtGain_1" permissions="Write, Save" value="0" />
<Key key="pmtOffset_0" permissions="Write, Save" value="0" />
<Key key="pmtOffset_1" permissions="Write, Save" value="0" />
<Key key="laserPower_0" permissions="Write, Save" value="18" />
<Key key="laserPowerCalibrated_0" permissions="Write, Save" value="0" />
<Key key="laserPowerAttenuation_0" permissions="Write, Save" value="0" />
<Key key="twophotonLaserPower_0" permissions="Write, Save" value="2926.17" />
<Key key="minVoltage_XAxis" permissions="Write, Save" value="-0.205995077821132" />
<Key key="minVoltage_YAxis" permissions="Write, Save" value="-0.855391548993729" />
<Key key="maxVoltage_XAxis" permissions="Write, Save" value="0.722359696628628" />
<Key key="maxVoltage_YAxis" permissions="Write, Save" value="0.0375257076868368" />
<Key key="imagingDevice" permissions="Write, Save" value="Ultima" />
</Frame>
<Frame relativeTime="0.191488" absoluteTime="9.296226" index="2" label="CurrentSettings">
<File channel="1" channelName="Ch1" preAmpID="0" filename="slice1_field1_500uA_stimB(+)-001_Cycle001_CurrentSettings_Ch1_000002.tif" />
<File channel="4" channelName="Spot" preAmpID="0" filename="slice1_field1_500uA_stimB(+)-001_Cycle001_CurrentSettings_Ch4_000002.tif" />
<ExtraParameters validData="True" />
<Key key="objectiveLens" permissions="Read, Write, Save" value="10X" />
<Key key="objectiveLensNA" permissions="Read, Write, Save" value="0.3" />
<Key key="objectiveLensMag" permissions="Read, Write, Save" value="10" />
<Key key="pixelsPerLine" permissions="Read, Write, Save" value="200" />
<Key key="linesPerFrame" permissions="Read, Write, Save" value="88" />
<Key key="systemType" permissions="Write, Save" value="0" />
<Key key="binningMode" permissions="Read, Write, Save" value="0" />
<Key key="frameAveraging" permissions="Read, Write, Save" value="0" />
<Key key="framePeriod" permissions="Read, Write, Save" value="0.191488" />
<Key key="scanlinePeriod" permissions="Read, Write, Save" value="0.002176" />
<Key key="dwellTime" permissions="Read, Write, Save" value="8" />
<Key key="bitDepth" permissions="Read, Write, Save" value="12" />
<Key key="positionCurrent_XAxis" permissions="Write, Save" value="19401.38671875" />
<Key key="positionCurrent_YAxis" permissions="Write, Save" value="-20993.3203125" />
<Key key="positionCurrent_ZAxis" permissions="Write, Save" value="15902.42" />
<Key key="zDevice" permissions="Write, Save" value="0" />
<Key key="rotation" permissions="Read, Write, Save" value="20" />
<Key key="opticalZoom" permissions="Read, Write, Save" value="1" />
<Key key="micronsPerPixel_XAxis" permissions="Read, Write, Save" value="0.219298245614035" />
<Key key="micronsPerPixel_YAxis" permissions="Read, Write, Save" value="0.219298245614035" />
<Key key="pmtGain_0" permissions="Write, Save" value="786.290322580645" />
<Key key="pmtGain_1" permissions="Write, Save" value="0" />
<Key key="pmtOffset_0" permissions="Write, Save" value="0" />
<Key key="pmtOffset_1" permissions="Write, Save" value="0" />
<Key key="laserPower_0" permissions="Write, Save" value="18" />
<Key key="laserPowerCalibrated_0" permissions="Write, Save" value="0" />
<Key key="laserPowerAttenuation_0" permissions="Write, Save" value="0" />
<Key key="twophotonLaserPower_0" permissions="Write, Save" value="2926.17" />
<Key key="minVoltage_XAxis" permissions="Write, Save" value="-0.205995077821132" />
<Key key="minVoltage_YAxis" permissions="Write, Save" value="-0.855391548993729" />
<Key key="maxVoltage_XAxis" permissions="Write, Save" value="0.722359696628628" />
<Key key="maxVoltage_YAxis" permissions="Write, Save" value="0.0375257076868368" />
<Key key="imagingDevice" permissions="Write, Save" value="Ultima" />
</Frame>
</Sequence>
</PVScan>

6 个评论
显示 4更早的评论 隐藏 4更早的评论

Geoff
Geoff 2012-3-27
Could you please format that as code? Edit, highlight all, hit the '{} code' button, save. Cheers.
Chris
Chris 2012-3-27
Sorry bout that, fixed.
Thomas
Thomas 2012-3-27
Chris I saved your xml file as test.xml
>>test_data=xml2struct('test.xml')
to get the second relativeTime
>> test_data.PVScan.Sequence.Frame{1,2}.Attributes.relativeTime
ans =
0.191488
Chris
Chris 2012-3-27
I keep getting this:
test_data =
PVScan: [1x1 struct]
Attempt to reference field of non-structure array.
Here's a link to a full xml file. http://dl.dropbox.com/u/91186/test.xml
Does this still work for you?
Chris
Chris 2012-3-27
I think it may have to do with the 655K filesize. I can get the proper return value when I only include a few frames in the xml file...
Chris
Chris 2012-3-27
Figured it out.
Had to use xpath, but could jump right to the node I wanted without mapping from the file (which was too big). Explanation here http://blogs.mathworks.com/desktop/2010/11/01/xml-and-matlab-navigating-a-tree/
[xmlfilename,pathname]=uigetfile('*.xml');
openxmlfilename = fullfile(pathname,xmlfilename);
xDoc=xmlread(openxmlfilename)
import javax.xml.xpath.*
factory = XPathFactory.newInstance;
xpath = factory.newXPath;
expression = xpath.compile('PVScan/Sequence/Frame[2]/@relativeTime');
relativeTime = expression.evaluate(xDoc, XPathConstants.NUMBER)

请先登录，再进行评论。

Jeffrey Warner
Jeffrey Warner 2024-4-2

0 个投票

Hello,
I am trying to read this xml file to return the current filter position (<FilterPosition>) which is 4, and the Position name and position ID under the <Position Defined> node. I have not dealt with xm; files before. I tried xmlread and that returned a null result. Any healp is greatly appreciated.
DOMnode = xmlread(flName).
DOMnode = [#document: null]
I could not upload the xml file. Here is the contents of the file.
<FW102CProfileModel xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:xsd="http://www.w3.org/2001/XMLSchema" Pcount="6">
<SpeedMode>HighSpeed</SpeedMode>
<TriggerMode>Input</TriggerMode>
<SensorMode>TurnOff</SensorMode>
<FilterPosition>4</FilterPosition>
<PositionDefined>
<FW102CFilterConfigMode>
<PositionName>OD0</PositionName>
<PositionID>1</PositionID>
</FW102CFilterConfigMode>
<FW102CFilterConfigMode>
<PositionName>OD0.2 (5232)</PositionName>
<PositionID>2</PositionID>
</FW102CFilterConfigMode>
<FW102CFilterConfigMode>
<PositionName>OD0.5 (5235)</PositionName>
<PositionID>3</PositionID>
</FW102CFilterConfigMode>
<FW102CFilterConfigMode>
<PositionName>OD1 (5240)</PositionName>
<PositionID>4</PositionID>
</FW102CFilterConfigMode>
<FW102CFilterConfigMode>
<PositionName>OD2 (5242)</PositionName>
<PositionID>5</PositionID>
</FW102CFilterConfigMode>
<FW102CFilterConfigMode>
<PositionName>OD2.5 (5243)</PositionName>
<PositionID>6</PositionID>
</FW102CFilterConfigMode>
</PositionDefined>
<SequenceDefined/>
</FW102CProfileModel>

类别

在 帮助中心 和 File Exchange 中查找有关 Structured Data and XML Documents 的更多信息

产品

标签

Community Treasure Hunt

Find the treasures in MATLAB Central and discover how the community can help you!

Start Hunting!

Translated by