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added source files for unit testing chapter(s), fixed some bugs in regular expressions chapter

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This commit is contained in:
Mark Pilgrim
2009-02-16 14:31:42 -05:00
parent 12562a1761
commit 29129df299
18 changed files with 1232 additions and 9 deletions
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regular-expressions.html
+9 -9
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@@ -209,7 +209,7 @@ characters. If you've used regular expressions in other languages (like Perl), t
<h3 id=tensandones>Checking for tens and ones</h3>
<p>Now let's expand the Roman numeral regular expression to cover the tens and ones place. This example shows the check for tens.
<pre class=screen>
<samp class=prompt>>>> </samp><kbd>pattern = '^M?M?M?M?(CM|CD|D?C?C?C?)(XC|XL|L?X?X?X?)$'</kbd>
<samp class=prompt>>>> </samp><kbd>pattern = '^M?M?M?(CM|CD|D?C?C?C?)(XC|XL|L?X?X?X?)$'</kbd>
<a><samp class=prompt>>>> </samp><kbd>re.search(pattern, 'MCMXL')</kbd> <span>&#x2460;</span></a>
<samp>&lt;_sre.SRE_Match object at 0x008EEB48></samp>
<a><samp class=prompt>>>> </samp><kbd>re.search(pattern, 'MCML')</kbd> <span>&#x2461;</span></a>
@@ -229,10 +229,10 @@ characters. If you've used regular expressions in other languages (like Perl), t
</ol>
<p>The expression for the ones place follows the same pattern. I'll spare you the details and show you the end result.
<pre class=screen>
<samp class=prompt>>>> </samp><kbd>pattern = '^M?M?M?M?(CM|CD|D?C?C?C?)(XC|XL|L?X?X?X?)(IX|IV|V?I?I?I?)$'</kbd>
<samp class=prompt>>>> </samp><kbd>pattern = '^M?M?M?(CM|CD|D?C?C?C?)(XC|XL|L?X?X?X?)(IX|IV|V?I?I?I?)$'</kbd>
</pre><p>So what does that look like using this alternate <code>{n,m}</code> syntax? This example shows the new syntax.
<pre class=screen>
<samp class=prompt>>>> </samp><kbd>pattern = '^M{0,4}(CM|CD|D?C{0,3})(XC|XL|L?X{0,3})(IX|IV|V?I{0,3})$'</kbd>
<samp class=prompt>>>> </samp><kbd>pattern = '^M{0,3}(CM|CD|D?C{0,3})(XC|XL|L?X{0,3})(IX|IV|V?I{0,3})$'</kbd>
<a><samp class=prompt>>>> </samp><kbd>re.search(pattern, 'MDLV')</kbd> <span>&#x2460;</span></a>
<samp>&lt;_sre.SRE_Match object at 0x008EEB48></samp>
<a><samp class=prompt>>>> </samp><kbd>re.search(pattern, 'MMDCLXVI')</kbd> <span>&#x2461;</span></a>
@@ -259,15 +259,15 @@ characters. If you've used regular expressions in other languages (like Perl), t
<p>This will be more clear with an example. Let's revisit the compact regular expression you've been working with, and make it a verbose regular expression. This example shows how.
<pre class=screen>
<samp class=prompt>>>> </samp><kbd>pattern = """
^ # beginning of string
M{0,4} # thousands - 0 to 4 M's
^ # beginning of string
M{0,3} # thousands - 0 to 3 M's
(CM|CD|D?C{0,3}) # hundreds - 900 (CM), 400 (CD), 0-300 (0 to 3 C's),
# or 500-800 (D, followed by 0 to 3 C's)
# or 500-800 (D, followed by 0 to 3 C's)
(XC|XL|L?X{0,3}) # tens - 90 (XC), 40 (XL), 0-30 (0 to 3 X's),
# or 50-80 (L, followed by 0 to 3 X's)
# or 50-80 (L, followed by 0 to 3 X's)
(IX|IV|V?I{0,3}) # ones - 9 (IX), 4 (IV), 0-3 (0 to 3 I's),
# or 5-8 (V, followed by 0 to 3 I's)
$ # end of string
# or 5-8 (V, followed by 0 to 3 I's)
$ # end of string
"""</kbd>
<a><samp class=prompt>>>> </samp><kbd>re.search(pattern, 'M', re.VERBOSE)</kbd> <span>&#x2460;</span></a>
<samp>&lt;_sre.SRE_Match object at 0x008EEB48></samp>