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<html><head><meta http-equiv="Content-Type" content="text/html; charset=UTF-8"><title>Troubleshooting input data</title><link rel="stylesheet" type="text/css" href="manual.css"><meta name="generator" content="DocBook XSL Stylesheets V1.76.0"><link rel="home" href="index.html" title="JpGraph Manual"><link rel="up" href="ch13.html" title="Chapter 13. Getting hold of the data to be displayed"></head><body bgcolor="white" text="black" link="#0000FF" vlink="#840084" alink="#0000FF"><div class="navheader"><table width="100%" summary="Navigation header"><tr><th colspan="3" align="center">Troubleshooting input data</th></tr><tr><td width="20%" align="left"> </td><th width="60%" align="center">Chapter 13. Getting hold of the data to be displayed</th><td width="20%" align="right"> </td></tr></table><hr></div><div class="sect1" title="Troubleshooting input data"><div class="titlepage"><div><div><h2 class="title" style="clear: both"><a name="id2539112"></a>Troubleshooting input data</h2></div></div></div>
<p>There are two common mistakes that causes problems with input data.</p>
<p>
</p><div class="orderedlist"><ol class="orderedlist" type="1"><li class="listitem">
<p>The indexes in the data array has missing keys. The library assumes
that the data array has consecutive values indexed from 0 and upwards.
This means that the following data array specification is <span class="bold"><strong>illegal</strong></span></p>
<p>
</p><div class="hl-main"><table class="hl-table" width="100%"><tr><td class="hl-gutter" align="right" valign="top"><pre>1
</pre></td><td class="hl-main" valign="top"><pre><span class="hl-code">$data = array( 1 => 23, 2 => 14, 3 => 17 ) ;</span></pre></td></tr></table></div><p>
</p>
<p>The problem with the array above is that it lacks the 0 key. A similar
problem is to have a missing index, such as</p>
<p>
</p><div class="hl-main"><table class="hl-table" width="100%"><tr><td class="hl-gutter" align="right" valign="top"><pre>1
</pre></td><td class="hl-main" valign="top"><pre><span class="hl-code">$data = array( 0 => 23, 2 => 14, 3 => 17 ) ;</span></pre></td></tr></table></div><p>
</p>
<p>If <code class="code">E_NOTICE</code> is not enabled in
<code class="filename">php.ini</code> then this mistake will give the
(slightly misleading) error message shown in <a class="xref" href="ch13s06.html#fig.only-null-error" title="Figure 13.7. Error when only null values are specified">Figure 13.7. Error when only null values are specified</a>. If full error checking is
enabled in php.ini then these types of problem will give the standard
PHP error message shown in <a class="xref" href="ch13s07.html#fig.php-htmlerr-missing-key" title="Figure 13.8. PHP (HTML) error when missing data keys">Figure 13.8. PHP (HTML) error when missing data keys</a>. This shows a PHP setup
which has HTML errors enabled. Note the JpGraph textual error string at
the bottom of the second PHP error message box.</p>
<p>
</p><div class="figure"><a name="fig.php-htmlerr-missing-key"></a><p class="title"><b>Figure 13.8. PHP (HTML) error when missing data keys</b></p><div class="figure-contents">
<div class="mediaobject"><img src="images/php-htmlerr-missing-key.png" alt="PHP (HTML) error when missing data keys"></div>
</div></div><p><br class="figure-break">
</p>
</li><li class="listitem">
<p>Another typical mistake caused by "faulty data" is different
convention for specifying decimal data. PHP and the library assumes that
decimal data used "." (point) to separate the integer from the decimal
part of a number. Some locales uses "," (comma) to do this separation.
This means that the following code will <span class="bold"><strong>not</strong></span> work.</p>
<p>
</p><div class="hl-main"><table class="hl-table" width="100%"><tr><td class="hl-gutter" align="right" valign="top"><pre>1
</pre></td><td class="hl-main" valign="top"><pre><span class="hl-code">$data = array( 0 => '12,0', 1 => '18,0', 2 => '15,0' ) ;</span></pre></td></tr></table></div><p>
</p>
<p>Again, if <code class="code">E_NOTICE</code> is not enabled in
<code class="filename">php.ini</code> then this mistake will give the
(slightly misleading) error message shown in <a class="xref" href="ch13s06.html#fig.only-null-error" title="Figure 13.7. Error when only null values are specified">Figure 13.7. Error when only null values are specified</a></p>
</li></ol></div><p>
</p>
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