Re: sort | uniq via keys

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Subject: Re: sort | uniq via keys
From: Wendell Piez <wapiez@xxxxxxxxxxxxxxxx>
Date: Thu, 14 Feb 2002 19:03:48 -0500

Hi Saverio,

At 03:30 PM 2/14/02, you wrote:

I am curious then as to the difference b/t the descendant, following,
and following-sibling axes.

This is something that a good book can help with: no need for me to explain here. Or consult the XPath Recommendation: it's quite clear. (Find it at w3.org.)

In addition, consider the following problem. Instead of sorting and uniqing the element names of `all' nodes in the input tree, I'd like to extract the names of elements residing at the same `level' in the input tree, assuming a balanced input tree.

There are (at least) two ways to approach this. One would be to declare different keys for different levels, such as

<xsl:key name="features1" match="/*/*" use="name()"/>

which would only get you back elements directly under the document element (in your case, a and b elements) since those are the only ones it matches.

Another way is by ordering the way you traverse the tree, and using keys as you are now doing only to control the uniqueness.

(Of course, it's still going to test uniqueness relative to the entire document, not just to the level you're on; if you want the latter, you have to use different keys as above.)

The much maligned and abused <xsl:for-each> can be applied to this. From the root, for-each select="*" will get you only one level deep, select="*/*" will get you only two levels deep, and so on. (In these XPaths, the child:: axis is implicit, so e.g. */* is short for child::*/child::*, that is grandchildren.)

Again, the secret is in XPath. Check out the spec: it's not that hard.

Good luck,
Wendell


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Wendell Piez                            mailto:wapiez@xxxxxxxxxxxxxxxx
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Current Thread

differences between fop 0.20 and 0.18.1-DEV?, (continued)
- Bryan Rasmussen - Thu, 14 Feb 2002 12:18:15 -0500 (EST)
- Thomas B. Passin - Thu, 14 Feb 2002 12:29:37 -0500 (EST)
- Wendell Piez - Thu, 14 Feb 2002 13:35:35 -0500 (EST)
  - Saverio Perugini - Thu, 14 Feb 2002 15:27:19 -0500 (EST)
    - Wendell Piez - Thu, 14 Feb 2002 19:01:32 -0500 (EST) <=
    - Saverio Perugini - Fri, 15 Feb 2002 17:15:59 -0500 (EST)
- Joerg Pietschmann - Fri, 15 Feb 2002 03:45:06 -0500 (EST)

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Re: sort \| uniq via keys, Saverio Perugini	Thread	Re: sort \| uniq via keys, Saverio Perugini
Re: match on attribute anywhe, Wendell Piez	Date	Re: xmlnx="" declarations app, Mike Brown
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