Capture xml tag and following related tag if one exists

Question

I'm looking to extract the programme title and sub-title from the (clipped) XML file below. I was extracting both individually using xmllint and sed and combining them into one file, but I have since discovered that there are the occasional entries that only have a title and no sub-title. In this case I would like to leave sub-title blank. Please could someone suggest a way to account for this discrepancy?

XML File

<programme start="20171013170000 +0100" stop="20171013180000 +0100" channel="b492458d826d592ec7c528545a16c757">
  <title lang="eng">Accessories Gift Hall</title>
  <sub-title lang="eng">Find the perfect gift with fashion accessories by some of our most sought-after brands. From chic purses and wallets to cosy PJs and slippers, there&apos;s something for everyone.</sub-title>
</programme>
<programme start="20171013180000 +0100" stop="20171014130000 +0100" channel="b492458d826d592ec7c528545a16c757">
  <title lang="eng">..programmes start again at 1pm</title>
</programme>
<programme start="20171014130000 +0100" stop="20171014140000 +0100" channel="b492458d826d592ec7c528545a16c757">
  <title lang="eng">Ruth Langsford&apos;s Fashion Edit</title>
  <sub-title lang="eng">TV personality and QVC fashion ambassador, Ruth Langsford, shares her favourite looks and must-have pieces that will transform your wardrobe and have you looking fabulously stylish.</sub-title>
</programme>

Bash commands v1

xmllint --xpath "//programme/title" xmltv | sed -r 's/\n//g' | sed 's/<\/title>/\n/g' | sed 's/<title lang="eng">//g' > 1.txt
xmllint --xpath "//programme/sub-title" xmltv | sed -r 's/\n//g' | sed 's/<\/sub-title>/\n/g' | sed 's/<sub-title lang="eng">//g' > 2.txt
paste <(cat 1.txt) <(cat 2.txt) > 3.txt

Thanks!

I think xmlstarlet would be a better choice for this task; would you be interested in an xmlstarlet solution? — Daniel Haley, Oct 23 '17 at 22:06
Yes please Daniel, I have heard of xmlstarlet too, I'm not entirely sure what the difference between it and xmllint is. — user2679016, Oct 23 '17 at 22:14
The difgference is that xmlstarlet display each result lines with newlines (not the case for xmllint) — Gilles Quénot, Oct 23 '17 at 22:45

score 2 · Accepted Answer · answered Oct 23 '17 at 22:18

Here's an example using the sel command of xmlstarlet from the command line...

$ xmlstarlet sel -T -t -m '//programme' -v 'concat(normalize-space(title)," ",normalize-space(sub-title))' -n input.xml
Accessories Gift Hall Find the perfect gift with fashion accessories by some of our most sought-after brands. From chic purses and wallets to cosy PJs and slippers, there's something for everyone.
..programmes start again at 1pm
Ruth Langsford's Fashion Edit TV personality and QVC fashion ambassador, Ruth Langsford, shares her favourite looks and must-have pieces that will transform your wardrobe and have you looking fabulously stylish.

I'm separating the title and sub-title by a single space, but that can be changed.

That looks correct and is super fast! I'm thinking I should learn xmlstarlet instead! Thanks! — user2679016, Oct 23 '17 at 22:33

score 0 · Answer 2 · answered Oct 23 '17 at 22:05

0

What I would do :

#!/bin/bash

count=$(xmllint --xpath "count(//programme)" /tmp/file.xml)

for ((i=1; i<=count; i++)); do
    xmllint --xpath "//programme[$i]/title/text()" /tmp/file.xml
    echo -n '|'
    xmllint --xpath "//programme[$i]/sub-title/text()" /tmp/file.xml
    echo
done

answered Oct 23 '17 at 22:05

Gilles Quénot

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Nice but slow. 15 minutes so far on the full file, plus a few "XPath set is empty" errors. – user2679016 Oct 23 '17 at 22:28

score 0 · Answer 3 · answered Oct 23 '17 at 22:13

0

In one pass with sed

sed '/<title/!d;N;/<sub-title/!s/\n.*//' XML File

answered Oct 23 '17 at 22:13

ctac_

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Until someone formats the XML and either the `title` or `subtitle` isn't all on the same line anymore. (https://stackoverflow.com/a/1732454/317052) – Daniel Haley Oct 23 '17 at 22:19
Yes I need to strip out the xml and have the title and sub-title next to each other ideally. – user2679016 Oct 23 '17 at 22:26

Capture xml tag and following related tag if one exists

3 Answers3