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| -rw-r--r-- | LectureNotesOnPython.html | 65 | ||||
| -rw-r--r-- | LectureNotesOnPython.rst | 51 |
2 files changed, 110 insertions, 6 deletions
diff --git a/LectureNotesOnPython.html b/LectureNotesOnPython.html index 3e55a72..6e8a1f7 100644 --- a/LectureNotesOnPython.html +++ b/LectureNotesOnPython.html @@ -685,6 +685,7 @@ A list of objects</dd> </div> </div> </blockquote> +<p>以上 <tt class="docutils literal"># [start,stop,step]</tt> 代表注释（comment），注释以 <tt class="docutils literal">#</tt> 号开头。</p> </div> <div class="section" id="concatenation"> <h1>字符串相加（concatenation）</h1> @@ -952,11 +953,17 @@ error-prone（易错）</p> <dd>return t[1:]</dd> </dl> </blockquote> +<dl class="docutils"> +<dt><strong>TDD</strong></dt> +<dd>Test-driven Development。测试驱动开发。 使用pytest。如何安装？ 使用命令 <tt class="docutils literal">pip install pytest</tt></dd> +</dl> +<p>用Big O表述复杂度。O(n)， O(n^2), O(n^3)。</p> +<p>密码实验回顾。</p> </div> <div class="section" id="dictionary"> <h1>字典（Dictionary）</h1> -<p>Mutable</p> -<p>超级有用</p> +<p>Mutable数据类型。</p> +<p>实际开发中超级有用。</p> <blockquote> <div class="line-block"> <div class="line">d = {} or d = dict()</div> @@ -977,7 +984,59 @@ error-prone（易错）</p> <p>value</p> <p>key-value pair (item)</p> <p>item的顺序不可预测，不是按照创建时的顺序。</p> -<p>练习：给定一个字符串，数出每个字母出现的频率。</p> +<p>练习：给定一个字符串，数出每个字母出现的频率。使用 <strong>Incremental Development</strong> 。</p> +<blockquote> +<div class="line-block"> +<div class="line">def histogram(s):</div> +<div class="line-block"> +<div class="line">''' Cannot pass any test cases. '''</div> +<div class="line">pass</div> +</div> +</div> +<div class="line-block"> +<div class="line">def histogram(s):</div> +<div class="line-block"> +<div class="line">''' Can pass the test case in which s is an empty string. '''</div> +<div class="line">d = {}</div> +<div class="line">return d</div> +</div> +</div> +<div class="line-block"> +<div class="line">def histogram(s):</div> +<div class="line-block"> +<div class="line">''' Can pass the test cases in which all characters in s are unique. '''</div> +<div class="line">d = {}</div> +<div class="line">for c in s:</div> +<div class="line-block"> +<div class="line">d[c] = 1</div> +</div> +<div class="line">return d</div> +</div> +</div> +<div class="line-block"> +<div class="line">def histogram(s):</div> +<div class="line-block"> +<div class="line">''' Can pass all test cases. '''</div> +<div class="line">d = {}</div> +<div class="line">for c in s:</div> +<div class="line-block"> +<div class="line">if c not in d:</div> +<div class="line-block"> +<div class="line">d[c] = 1</div> +</div> +<div class="line">else:</div> +<div class="line-block"> +<div class="line">d[c] += 1</div> +</div> +</div> +<div class="line">return d</div> +</div> +</div> +<div class="line-block"> +<div class="line">h = histogram('good')</div> +<div class="line">print(h)</div> +</div> +</blockquote> <p>练习：给定一个字符串，数出每个单词出现的频率。</p> </div> <div class="section" id="id9"> diff --git a/LectureNotesOnPython.rst b/LectureNotesOnPython.rst index 52b2c2c..b47b929 100644 --- a/LectureNotesOnPython.rst +++ b/LectureNotesOnPython.rst @@ -349,6 +349,9 @@ len()函数。返回字符串字符个数。len(fruit)。 | print(c) +以上 ``# [start,stop,step]`` 代表注释（comment），注释以 ``#`` 号开头。 + + 字符串相加（concatenation） ------------------------------------------------------- @@ -638,14 +641,25 @@ error-prone（易错） return t[1:] +**TDD** + Test-driven Development。测试驱动开发。 使用pytest。如何安装？ 使用命令 ``pip install pytest`` + + + +用Big O表述复杂度。O(n)， O(n^2), O(n^3)。 + + + +密码实验回顾。 + 字典（Dictionary） --------------------------------- -Mutable +Mutable数据类型。 -超级有用 +实际开发中超级有用。 | d = {} or d = dict() @@ -666,7 +680,38 @@ key-value pair (item) item的顺序不可预测，不是按照创建时的顺序。 -练习：给定一个字符串，数出每个字母出现的频率。 +练习：给定一个字符串，数出每个字母出现的频率。使用 **Incremental Development** 。 + + | def histogram(s): + | ''' Cannot pass any test cases. ''' + | pass + + | def histogram(s): + | ''' Can pass the test case in which s is an empty string. ''' + | d = {} + | return d + + | def histogram(s): + | ''' Can pass the test cases in which all characters in s are unique. ''' + | d = {} + | for c in s: + | d[c] = 1 + | return d + + | def histogram(s): + | ''' Can pass all test cases. ''' + | d = {} + | for c in s: + | if c not in d: + | d[c] = 1 + | else: + | d[c] += 1 + | return d + + + | h = histogram('good') + | print(h) + 练习：给定一个字符串，数出每个单词出现的频率。 |