How to find elements by 'id' field in SVG file using Python

Question

The following is a snippet of the .svg file (which is xml):

   <text
       xml:space="preserve"
       style="font-size:14.19380379px;font-style:normal;font-variant:normal;font-weight:normal;font-stretch:normal;text-align:start;line-height:125%;writing-mode:lr-tb;text-anchor:start;fill:#000000;fill-opacity:1;stroke:none;font-family:DejaVu Sans Mono;-inkscape-font-specification:DejaVu Sans Mono"
       x="109.38555"
       y="407.02847"
       id="libcode-00"
       sodipodi:linespacing="125%"
       inkscape:label="#text4638"><tspan
         sodipodi:role="line"
         id="tspan4640"
         x="109.38555"
         y="407.02847">12345678</tspan></text>

I am learning Python and have no idea how to find all those elements textthat have a field idequal libcode-XXto where XX is a number.

I downloaded this .svg file using a mini parser and tried to find the elements using getElementById. However, I get the result None.

    svgTemplate = minidom.parse(svgFile)
    print svgTemplate
    print svgTemplate.getElementById('libcode-00')

Following other SO questions, I tried using setIdAttribute('id')on the svgTemplatesite with no luck.

: text, id libcode-XX. tspan .

Answer 1

, -. , svg, .

lxml.etree. XPATH XML-. , .

SO XPATH etree. .

from lxml import etree
data = """
 <svg
    xmlns:dc="http://purl.org/dc/elements/1.1/"
    xmlns:cc="http://web.resource.org/cc/"
    xmlns:rdf="http://www.w3.org/1999/02/22-rdf-syntax-ns#"
    xmlns:svg="http://www.w3.org/2000/svg"
    xmlns="http://www.w3.org/2000/svg"
    xmlns:xlink="http://www.w3.org/1999/xlink"
    xmlns:sodipodi="http://sodipodi.sourceforge.net/DTD/sodipodi-0.dtd"
    xmlns:inkscape="http://www.inkscape.org/namespaces/inkscape"
    width="50"
    height="25"
    id="svg2"
    sodipodi:version="0.32"
    inkscape:version="0.45.1"
    version="1.0"
    sodipodi:docbase="/home/tcooksey/Projects/qt-4.4/demos/embedded/embeddedsvgviewer/files"
    sodipodi:docname="v-slider-handle.svg"
    inkscape:output_extension="org.inkscape.output.svg.inkscape">
    <text
       xml:space="preserve"
       style="font-size:14.19380379px;font-style:normal;font-variant:normal;font-weight:normal;font-stretch:normal;text-align:start;line-height:125%;writing-mode:lr-tb;text-anchor:start;fill:#000000;fill-opacity:1;stroke:none;font-family:DejaVu Sans Mono;-inkscape-font-specification:DejaVu Sans Mono"
       x="109.38555"
       y="407.02847"
       id="libcode-00"
       sodipodi:linespacing="125%"
       inkscape:label="#text4638"><tspan
         sodipodi:role="line"
         id="tspan4640"
         x="109.38555"
         y="407.02847">12345678</tspan></text>
    </svg>
"""

nsmap = {
    'sodipodi': 'http://sodipodi.sourceforge.net/DTD/sodipodi-0.dtd',
    'cc': 'http://web.resource.org/cc/',
    'svg': 'http://www.w3.org/2000/svg',
    'dc': 'http://purl.org/dc/elements/1.1/',
    'xlink': 'http://www.w3.org/1999/xlink',
    'rdf': 'http://www.w3.org/1999/02/22-rdf-syntax-ns#',
    'inkscape': 'http://www.inkscape.org/namespaces/inkscape'
    }


data = etree.XML(data)

# All svg text elements
>>> data.xpath('//svg:text',namespaces=nsmap)
[<Element {http://www.w3.org/2000/svg}text at b7cfc9dc>]
# All svg text elements with id="libcode-00"
>>> data.xpath('//svg:text[@id="libcode-00"]',namespaces=nsmap)
[<Element {http://www.w3.org/2000/svg}text at b7cfc9dc>]
# TSPAN child elements of text elements with id="libcode-00"
>>> data.xpath('//svg:text[@id="libcode-00"]/svg:tspan',namespaces=nsmap)
[<Element {http://www.w3.org/2000/svg}tspan at b7cfc964>]
# All text elements with id starting with "libcode"
>>> data.xpath('//svg:text[fn:startswith(@id,"libcode")]',namespaces=nsmap)
[<Element {http://www.w3.org/2000/svg}text at b7cfcc34>]
# Iterate text elements, access tspan child
>>> for elem in data.xpath('//svg:text[fn:startswith(@id,"libcode")]',namespaces=nsmap):
...     tp = elem.xpath('./svg:tspan',namespaces=nsmap)[0]
...     tp.text = "new text"

open("newfile.svg","w").write(etree.tostring(data))

Answer 2

, 'id' 'xml: id'?

minidom svg, 'id' , . svg id svg- , xml, DTD, , . DTD XML, svg-aware.

'id' SVG 1.1 DTD: http://www.w3.org/TR/SVG11/svgdtd.html#DTD.1.4

Answer 3

MattH, xpath, , ,

pub_name = data.xpath('//dc:publisher/cc:Agent/dc:title',
                            namespaces=nsmap)[0].text

, .