432 lines
13 KiB
HTML
432 lines
13 KiB
HTML
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN"
|
|
"http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd">
|
|
<html>
|
|
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8"/>
|
|
<head>
|
|
<title>Penlight Documentation</title>
|
|
<link rel="stylesheet" href="../ldoc.css" type="text/css" />
|
|
</head>
|
|
<body>
|
|
|
|
<div id="container">
|
|
|
|
<div id="product">
|
|
<div id="product_logo"></div>
|
|
<div id="product_name"><big><b></b></big></div>
|
|
<div id="product_description"></div>
|
|
</div> <!-- id="product" -->
|
|
|
|
|
|
<div id="main">
|
|
|
|
|
|
<!-- Menu -->
|
|
|
|
<div id="navigation">
|
|
<br/>
|
|
<h1>Penlight</h1>
|
|
|
|
<ul>
|
|
<li><a href="../index.html">Index</a></li>
|
|
</ul>
|
|
|
|
<h2>Contents</h2>
|
|
<ul>
|
|
<li><a href="#Functions">Functions</a></li>
|
|
</ul>
|
|
|
|
|
|
<h2>Modules</h2>
|
|
<ul>
|
|
<li><a href="../modules/pl.html">pl</a></li>
|
|
<li><a href="../modules/pl.Date.html">pl.Date</a></li>
|
|
<li><a href="../modules/pl.List.html">pl.List</a></li>
|
|
<li><a href="../modules/pl.Map.html">pl.Map</a></li>
|
|
<li><a href="../modules/pl.MultiMap.html">pl.MultiMap</a></li>
|
|
<li><a href="../modules/pl.OrderedMap.html">pl.OrderedMap</a></li>
|
|
<li><a href="../modules/pl.Set.html">pl.Set</a></li>
|
|
<li><a href="../modules/pl.app.html">pl.app</a></li>
|
|
<li><a href="../modules/pl.array2d.html">pl.array2d</a></li>
|
|
<li><a href="../modules/pl.class.html">pl.class</a></li>
|
|
<li><a href="../modules/pl.comprehension.html">pl.comprehension</a></li>
|
|
<li><a href="../modules/pl.config.html">pl.config</a></li>
|
|
<li><strong>pl.data</strong></li>
|
|
<li><a href="../modules/pl.dir.html">pl.dir</a></li>
|
|
<li><a href="../modules/pl.file.html">pl.file</a></li>
|
|
<li><a href="../modules/pl.func.html">pl.func</a></li>
|
|
<li><a href="../modules/pl.input.html">pl.input</a></li>
|
|
<li><a href="../modules/pl.lapp.html">pl.lapp</a></li>
|
|
<li><a href="../modules/pl.lexer.html">pl.lexer</a></li>
|
|
<li><a href="../modules/pl.luabalanced.html">pl.luabalanced</a></li>
|
|
<li><a href="../modules/pl.operator.html">pl.operator</a></li>
|
|
<li><a href="../modules/pl.path.html">pl.path</a></li>
|
|
<li><a href="../modules/pl.permute.html">pl.permute</a></li>
|
|
<li><a href="../modules/pl.pretty.html">pl.pretty</a></li>
|
|
<li><a href="../modules/pl.seq.html">pl.seq</a></li>
|
|
<li><a href="../modules/pl.sip.html">pl.sip</a></li>
|
|
<li><a href="../modules/pl.strict.html">pl.strict</a></li>
|
|
<li><a href="../modules/pl.stringio.html">pl.stringio</a></li>
|
|
<li><a href="../modules/pl.stringx.html">pl.stringx</a></li>
|
|
<li><a href="../modules/pl.tablex.html">pl.tablex</a></li>
|
|
<li><a href="../modules/pl.template.html">pl.template</a></li>
|
|
<li><a href="../modules/pl.test.html">pl.test</a></li>
|
|
<li><a href="../modules/pl.text.html">pl.text</a></li>
|
|
<li><a href="../modules/pl.utils.html">pl.utils</a></li>
|
|
<li><a href="../modules/pl.xml.html">pl.xml</a></li>
|
|
</ul>
|
|
<h2>Topics</h2>
|
|
<ul>
|
|
<li><a href="../topics/01-introduction.md.html">01-introduction.md</a></li>
|
|
<li><a href="../topics/02-arrays.md.html">02-arrays.md</a></li>
|
|
<li><a href="../topics/03-strings.md.html">03-strings.md</a></li>
|
|
<li><a href="../topics/04-paths.md.html">04-paths.md</a></li>
|
|
<li><a href="../topics/05-dates.md.html">05-dates.md</a></li>
|
|
<li><a href="../topics/06-data.md.html">06-data.md</a></li>
|
|
<li><a href="../topics/07-functional.md.html">07-functional.md</a></li>
|
|
<li><a href="../topics/08-additional.md.html">08-additional.md</a></li>
|
|
<li><a href="../topics/09-discussion.md.html">09-discussion.md</a></li>
|
|
</ul>
|
|
<h2>Examples</h2>
|
|
<ul>
|
|
<li><a href="../examples/seesubst.lua.html">seesubst.lua</a></li>
|
|
<li><a href="../examples/sipscan.lua.html">sipscan.lua</a></li>
|
|
<li><a href="../examples/symbols.lua.html">symbols.lua</a></li>
|
|
<li><a href="../examples/test-cmp.lua.html">test-cmp.lua</a></li>
|
|
<li><a href="../examples/test-data.lua.html">test-data.lua</a></li>
|
|
<li><a href="../examples/test-listcallbacks.lua.html">test-listcallbacks.lua</a></li>
|
|
<li><a href="../examples/test-pretty.lua.html">test-pretty.lua</a></li>
|
|
<li><a href="../examples/test-symbols.lua.html">test-symbols.lua</a></li>
|
|
<li><a href="../examples/testapp.lua.html">testapp.lua</a></li>
|
|
<li><a href="../examples/testclone.lua.html">testclone.lua</a></li>
|
|
<li><a href="../examples/testconfig.lua.html">testconfig.lua</a></li>
|
|
<li><a href="../examples/testglobal.lua.html">testglobal.lua</a></li>
|
|
<li><a href="../examples/testinputfields.lua.html">testinputfields.lua</a></li>
|
|
<li><a href="../examples/testinputfields2.lua.html">testinputfields2.lua</a></li>
|
|
<li><a href="../examples/testxml.lua.html">testxml.lua</a></li>
|
|
<li><a href="../examples/which.lua.html">which.lua</a></li>
|
|
</ul>
|
|
|
|
</div>
|
|
|
|
<div id="content">
|
|
|
|
<h1>Module <code>pl.data</code></h1>
|
|
|
|
<p>Reading and querying simple tabular data.</p>
|
|
<p><pre><code>data.read 'test.txt'
|
|
==> {{10,20},{2,5},{40,50},fieldnames={'x','y'},delim=','}
|
|
</code></pre>
|
|
|
|
<p> Provides a way of creating basic SQL-like queries.</p>
|
|
|
|
<pre><code>require 'pl'
|
|
local d = data.read('xyz.txt')
|
|
local q = d:select('x,y,z where x > 3 and z < 2 sort by y')
|
|
for x,y,z in q do
|
|
print(x,y,z)
|
|
end
|
|
</code></pre>
|
|
|
|
<p> See <a href="../topics/06-data.md.html#Reading_Columnar_Data">the Guide</a></p>
|
|
|
|
<p> Dependencies: <a href="../modules/pl.utils.html#">pl.utils</a> , <a href="../modules/pl.array2d.html#">pl.array2d</a> (fallback methods)</p>
|
|
</p>
|
|
|
|
<h2><a href="#Functions">Functions</a></h2>
|
|
<table class="function_list">
|
|
<tr>
|
|
<td class="name" nowrap><a href="#Data.column_by_name">Data.column_by_name (name)</a></td>
|
|
<td class="summary">return a particular column as a list of values (method).</td>
|
|
</tr>
|
|
<tr>
|
|
<td class="name" nowrap><a href="#Data.select">Data.select (condn)</a></td>
|
|
<td class="summary">return a query iterator on this data (method).</td>
|
|
</tr>
|
|
<tr>
|
|
<td class="name" nowrap><a href="#Data.select_row">Data.select_row (condn)</a></td>
|
|
<td class="summary">return a row iterator on this data (method).</td>
|
|
</tr>
|
|
<tr>
|
|
<td class="name" nowrap><a href="#Data.copy_select">Data.copy_select (condn)</a></td>
|
|
<td class="summary">return a new data object based on this query (method).</td>
|
|
</tr>
|
|
<tr>
|
|
<td class="name" nowrap><a href="#Data.column_names">Data.column_names ()</a></td>
|
|
<td class="summary">return the field names of this data object (method).</td>
|
|
</tr>
|
|
<tr>
|
|
<td class="name" nowrap><a href="#Data.write_row">Data.write_row (f)</a></td>
|
|
<td class="summary">write out a row (method).</td>
|
|
</tr>
|
|
<tr>
|
|
<td class="name" nowrap><a href="#Data.write">Data.write (f)</a></td>
|
|
<td class="summary">write data out to file (method).</td>
|
|
</tr>
|
|
<tr>
|
|
<td class="name" nowrap><a href="#read">read (file, cnfg)</a></td>
|
|
<td class="summary">read a delimited file in a Lua table.</td>
|
|
</tr>
|
|
<tr>
|
|
<td class="name" nowrap><a href="#write">write (data, file, fieldnames, delim)</a></td>
|
|
<td class="summary">write 2D data to a file.</td>
|
|
</tr>
|
|
<tr>
|
|
<td class="name" nowrap><a href="#new">new (d, fieldnames)</a></td>
|
|
<td class="summary">create a new dataset from a table of rows.</td>
|
|
</tr>
|
|
<tr>
|
|
<td class="name" nowrap><a href="#query">query (data, condn, context, return_row)</a></td>
|
|
<td class="summary">create a query iterator from a select string.</td>
|
|
</tr>
|
|
<tr>
|
|
<td class="name" nowrap><a href="#filter">filter (Q, infile, outfile, dont_fail)</a></td>
|
|
<td class="summary">Filter input using a query.</td>
|
|
</tr>
|
|
</table>
|
|
|
|
<br/>
|
|
<br/>
|
|
|
|
|
|
<h2><a name="Functions"></a>Functions</h2>
|
|
|
|
<dl class="function">
|
|
<dt>
|
|
<a name = "Data.column_by_name"></a>
|
|
<strong>Data.column_by_name (name)</strong>
|
|
</dt>
|
|
<dd>
|
|
return a particular column as a list of values (method).
|
|
|
|
<h3>Parameters:</h3>
|
|
<ul>
|
|
<li><code><em>name</em></code>: either name of column, or numerical index.</li>
|
|
</ul>
|
|
|
|
|
|
|
|
|
|
</dd>
|
|
<dt>
|
|
<a name = "Data.select"></a>
|
|
<strong>Data.select (condn)</strong>
|
|
</dt>
|
|
<dd>
|
|
return a query iterator on this data (method).
|
|
|
|
<h3>Parameters:</h3>
|
|
<ul>
|
|
<li><code><em>condn</em></code>: the query expression</li>
|
|
</ul>
|
|
|
|
|
|
|
|
|
|
<h3>see also:</h3>
|
|
<ul>
|
|
<a href="../modules/pl.data.html#query">data.query</a>
|
|
</ul>
|
|
</dd>
|
|
<dt>
|
|
<a name = "Data.select_row"></a>
|
|
<strong>Data.select_row (condn)</strong>
|
|
</dt>
|
|
<dd>
|
|
return a row iterator on this data (method).
|
|
|
|
<h3>Parameters:</h3>
|
|
<ul>
|
|
<li><code><em>condn</em></code>: the query expression</li>
|
|
</ul>
|
|
|
|
|
|
|
|
|
|
</dd>
|
|
<dt>
|
|
<a name = "Data.copy_select"></a>
|
|
<strong>Data.copy_select (condn)</strong>
|
|
</dt>
|
|
<dd>
|
|
return a new data object based on this query (method).
|
|
|
|
<h3>Parameters:</h3>
|
|
<ul>
|
|
<li><code><em>condn</em></code>: the query expression</li>
|
|
</ul>
|
|
|
|
|
|
|
|
|
|
</dd>
|
|
<dt>
|
|
<a name = "Data.column_names"></a>
|
|
<strong>Data.column_names ()</strong>
|
|
</dt>
|
|
<dd>
|
|
return the field names of this data object (method).
|
|
|
|
|
|
|
|
|
|
|
|
</dd>
|
|
<dt>
|
|
<a name = "Data.write_row"></a>
|
|
<strong>Data.write_row (f)</strong>
|
|
</dt>
|
|
<dd>
|
|
write out a row (method).
|
|
|
|
<h3>Parameters:</h3>
|
|
<ul>
|
|
<li><code><em>f</em></code>: file-like object</li>
|
|
</ul>
|
|
|
|
|
|
|
|
|
|
</dd>
|
|
<dt>
|
|
<a name = "Data.write"></a>
|
|
<strong>Data.write (f)</strong>
|
|
</dt>
|
|
<dd>
|
|
write data out to file (method).
|
|
|
|
<h3>Parameters:</h3>
|
|
<ul>
|
|
<li><code><em>f</em></code>: file-like object</li>
|
|
</ul>
|
|
|
|
|
|
|
|
|
|
</dd>
|
|
<dt>
|
|
<a name = "read"></a>
|
|
<strong>read (file, cnfg)</strong>
|
|
</dt>
|
|
<dd>
|
|
read a delimited file in a Lua table.
|
|
By default, attempts to treat first line as separated list of fieldnames.
|
|
|
|
<h3>Parameters:</h3>
|
|
<ul>
|
|
<li><code><em>file</em></code>: a filename or a file-like object (default stdin)</li>
|
|
<li><code><em>cnfg</em></code>: options table: can override delim (a string pattern), fieldnames (a list),
|
|
specify no_convert (default is to convert), numfields (indices of columns known
|
|
to be numbers) and thousands_dot (thousands separator in Excel CSV is ‘.’)</li>
|
|
</ul>
|
|
|
|
|
|
|
|
|
|
</dd>
|
|
<dt>
|
|
<a name = "write"></a>
|
|
<strong>write (data, file, fieldnames, delim)</strong>
|
|
</dt>
|
|
<dd>
|
|
write 2D data to a file.
|
|
Does not assume that the data has actually been
|
|
generated with <a href="../modules/pl.data.html#new">new</a> or <a href="../modules/pl.data.html#read">read</a> .
|
|
|
|
<h3>Parameters:</h3>
|
|
<ul>
|
|
<li><code><em>data</em></code>: 2D array</li>
|
|
<li><code><em>file</em></code>: filename or file-like object</li>
|
|
<li><code><em>fieldnames</em></code>: list of fields (optional)</li>
|
|
<li><code><em>delim</em></code>: delimiter (default tab)</li>
|
|
</ul>
|
|
|
|
|
|
|
|
|
|
</dd>
|
|
<dt>
|
|
<a name = "new"></a>
|
|
<strong>new (d, fieldnames)</strong>
|
|
</dt>
|
|
<dd>
|
|
create a new dataset from a table of rows. <br>
|
|
Can specify the fieldnames, else the table must have a field called
|
|
‘fieldnames’, which is either a string of delimiter-separated names,
|
|
or a table of names. <br>
|
|
If the table does not have a field called ‘delim’, then an attempt will be
|
|
made to guess it from the fieldnames string, defaults otherwise to tab.
|
|
|
|
<h3>Parameters:</h3>
|
|
<ul>
|
|
<li><code><em>d</em></code>: the table.</li>
|
|
<li><code><em>fieldnames</em></code>: optional fieldnames</li>
|
|
</ul>
|
|
|
|
|
|
<h3>Returns:</h3>
|
|
<ol>
|
|
the table.
|
|
</ol>
|
|
|
|
|
|
</dd>
|
|
<dt>
|
|
<a name = "query"></a>
|
|
<strong>query (data, condn, context, return_row)</strong>
|
|
</dt>
|
|
<dd>
|
|
create a query iterator from a select string.
|
|
Select string has this format: <br>
|
|
FIELDLIST [ where LUA-CONDN [ sort by FIELD] ]<br>
|
|
FIELDLIST is a comma-separated list of valid fields, or ‘*’. <br> <br>
|
|
The condition can also be a table, with fields ‘fields’ (comma-sep string or
|
|
table), ‘sort_by’ (string) and ‘where’ (Lua expression string or function)
|
|
|
|
<h3>Parameters:</h3>
|
|
<ul>
|
|
<li><code><em>data</em></code>: table produced by read</li>
|
|
<li><code><em>condn</em></code>: select string or table</li>
|
|
<li><code><em>context</em></code>: a list of tables to be searched when resolving functions</li>
|
|
<li><code><em>return_row</em></code>: if true, wrap the results in a row table</li>
|
|
</ul>
|
|
|
|
|
|
<h3>Returns:</h3>
|
|
<ol>
|
|
<li>an iterator over the specified fields, or nil</li>
|
|
<li>an error message</li>
|
|
</ol>
|
|
|
|
|
|
</dd>
|
|
<dt>
|
|
<a name = "filter"></a>
|
|
<strong>filter (Q, infile, outfile, dont_fail)</strong>
|
|
</dt>
|
|
<dd>
|
|
Filter input using a query.
|
|
|
|
<h3>Parameters:</h3>
|
|
<ul>
|
|
<li><code><em>Q</em></code>: a query string</li>
|
|
<li><code><em>infile</em></code>: filename or file-like object</li>
|
|
<li><code><em>outfile</em></code>: filename or file-like object</li>
|
|
<li><code><em>dont_fail</em></code>: true if you want to return an error, not just fail</li>
|
|
</ul>
|
|
|
|
|
|
|
|
|
|
</dd>
|
|
</dl>
|
|
|
|
|
|
</div> <!-- id="content" -->
|
|
</div> <!-- id="main" -->
|
|
<div id="about">
|
|
<i>generated by <a href="http://github.com/stevedonovan/LDoc">LDoc 1.2</a></i>
|
|
</div> <!-- id="about" -->
|
|
</div> <!-- id="container" -->
|
|
</body>
|
|
</html>
|