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colorize interactive shell examples

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Mark Pilgrim
2009-06-08 22:43:48 -04:00
parent cd6260adf1
commit be2b7d3546
16 changed files with 1003 additions and 1020 deletions
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case-study-porting-chardet-to-python-3.html
+15 -15
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@@ -795,23 +795,23 @@ TypeError: unsupported operand type(s) for +: 'int' and 'bytes'</samp></pre>
<aside>Each item in a string is a string. Each item in a byte array is an integer.</aside>
<p>This error doesn&#8217;t occur the first time the <code>feed()</code> method gets called; it occurs the <em>second time</em>, after <var>self._mLastChar</var> has been set to the last byte of <var>aBuf</var>. Well, what&#8217;s the problem with that? Getting a single element from a byte array yields an integer, not a byte array. To see the difference, follow me to the interactive shell:
<pre class=screen>
<a><samp class=p>>>> </samp><kbd>aBuf = b'\xEF\xBB\xBF'</kbd> <span class=u>&#x2460;</span></a>
<samp class=p>>>> </samp><kbd>len(aBuf)</kbd>
<samp>3</samp>
<samp class=p>>>> </samp><kbd>mLastChar = aBuf[-1]</kbd>
<a><samp class=p>>>> </samp><kbd>mLastChar</kbd> <span class=u>&#x2461;</span></a>
<samp>191</samp>
<a><samp class=p>>>> </samp><kbd>type(mLastChar)</kbd> <span class=u>&#x2462;</span></a>
<samp>&lt;class 'int'></samp>
<a><samp class=p>>>> </samp><kbd>mLastChar + aBuf</kbd> <span class=u>&#x2463;</span></a>
<a><samp class=p>>>> </samp><kbd class=pp>aBuf = b'\xEF\xBB\xBF'</kbd> <span class=u>&#x2460;</span></a>
<samp class=p>>>> </samp><kbd class=pp>len(aBuf)</kbd>
<samp class=pp>3</samp>
<samp class=p>>>> </samp><kbd class=pp>mLastChar = aBuf[-1]</kbd>
<a><samp class=p>>>> </samp><kbd class=pp>mLastChar</kbd> <span class=u>&#x2461;</span></a>
<samp class=pp>191</samp>
<a><samp class=p>>>> </samp><kbd class=pp>type(mLastChar)</kbd> <span class=u>&#x2462;</span></a>
<samp class=pp>&lt;class 'int'></samp>
<a><samp class=p>>>> </samp><kbd class=pp>mLastChar + aBuf</kbd> <span class=u>&#x2463;</span></a>
<samp class=traceback>Traceback (most recent call last):
File "&lt;stdin>", line 1, in &lt;module>
TypeError: unsupported operand type(s) for +: 'int' and 'bytes'</samp>
<a><samp class=p>>>> </samp><kbd>mLastChar = aBuf[-1:]</kbd> <span class=u>&#x2464;</span></a>
<samp class=p>>>> </samp><kbd>mLastChar</kbd>
<samp>b'\xbf'</samp>
<a><samp class=p>>>> </samp><kbd>mLastChar + aBuf</kbd> <span class=u>&#x2465;</span></a>
<samp>b'\xbf\xef\xbb\xbf'</samp></pre>
<a><samp class=p>>>> </samp><kbd class=pp>mLastChar = aBuf[-1:]</kbd> <span class=u>&#x2464;</span></a>
<samp class=p>>>> </samp><kbd class=pp>mLastChar</kbd>
<samp class=pp>b'\xbf'</samp>
<a><samp class=p>>>> </samp><kbd class=pp>mLastChar + aBuf</kbd> <span class=u>&#x2465;</span></a>
<samp class=pp>b'\xbf\xef\xbb\xbf'</samp></pre>
<ol>
<li>Define a byte array of length 3.
<li>The last element of the byte array is 191.
@@ -901,7 +901,7 @@ def feed(self, aBuf):
<pre class=screen><samp class=p>C:\home\chardet> </samp><kbd>python test.py tests\*\*</kbd>
<samp>tests\ascii\howto.diveintomark.org.xml ascii with confidence 1.0
tests\Big5\0804.blogspot.com.xml</samp>
<samp>Traceback (most recent call last):
<samp class=traceback>Traceback (most recent call last):
File "test.py", line 10, in &lt;module>
u.feed(line)
File "C:\home\chardet\chardet\universaldetector.py", line 116, in feed