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4.6 KiB
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70 lines
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4.6 KiB
HTML
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<title>CLiki: xarray</title>
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<span class="hidden">CLiki - xarray</span>
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<div id="content"><div id="content-area"><div id="article-title">xarray</div><div id="article">This package implements a generalized interface for array-like
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objects. The idea is that we should be able to index an object as
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<div class="code"><span class="nonparen"><span class="paren1">(<span class="nonparen">xref object 1 2 3</span>)</span>
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</span></div>
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to retrieve or set an element. This would be easy to do it aref was a
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generic function, but it is not. I describe a simple interface with a
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few generic functions (xdims queries dimensions, xtype element type,
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etc), any objects that has these methods is called "xrefable".<p>The nice part is that views on an array can also be xrefable. For an
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two-dimensional array <code>*a*</code>,
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<div class="code"><span class="nonparen"><span class="paren1">(<span class="nonparen">slice <span class="special">*a*</span> <span class="keyword">:all</span> 4</span>)</span>
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</span></div>
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selects the 4th column of an array.¹ This view is also xrefable, so
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you can use<p><div class="code"><span class="nonparen"><span class="paren1">(<span class="nonparen"><a href="https://www.cliki.net/site/HyperSpec/Body/any_setf.html" class="symbol">setf</a> <span class="paren2">(<span class="nonparen">xref <span class="paren3">(<span class="nonparen">slice <span class="special">*a*</span> <span class="keyword">:all</span> 4</span>)</span> 2</span>)</span> 9</span>)</span>
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</span></div>
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to set element 2 to <code>9</code>. Changes will be made in the original array
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<code>*a*</code>, since this is a view. But for functions that just expect an
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array, they can use the interface (xref, xdims, etc) and not care
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where it is coming from.<p>¹ The slice interface is similar to author's <a href="https://www.cliki.net/affi" class="new">affi</a> package, but now
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arbitrary index vectors are allowed.<p>Homepage: <a href="https://github.com/blindglobe/xarray">https://github.com/blindglobe/xarray</a><p>License: <a href="MIT.html" class="category">MIT</a><p>See Also: <a href="cl-slice.html" class="internal">cl-slice</a><p><hr>
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Topics: <a href="language extension.html" class="category">language extension</a></div></div>
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