113 lines
2.9 KiB
Markdown
113 lines
2.9 KiB
Markdown
# 计算器
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## 需求
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- 编写一个简单的计算器，在数组中存入算式字符串，然后在新的数组中计算得到答案
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- 例如，有个数组是`["5 + 3", "6 * 2", "12 / 3", "100 - 55"]`
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- 得到的输出是`[8, 12, 4, 45]`
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## 参考代码
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```python
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# 示例输入
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expressions = ["5 + 3", "6 * 2", "12 / 3", "100 - 55"]
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# 创建一个新的数组，用来存储计算结果
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results = []
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# 遍历数组
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for i in expressions:
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# 将算式的两个数字取出
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a = int(i.split(" ")[0])
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b = int(i.split(" ")[-1])
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# 判断需要使用什么运算
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if i.count("+"):
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results.append(a + b)
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elif i.count("-"):
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results.append(a - b)
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elif i.count("*"):
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results.append(a * b)
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elif i.count("/"):
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results.append(a / b)
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print(results)
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```
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## 扩展学习
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- 貌似下面的代码更加合适，想办法去搞懂吧
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```python
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# 示例输入
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expressions = ["5 + 3", "6 * 2", "12 / 3", "100 - 55"]
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# 创建一个新的数组，用来存储计算结果
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results = []
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# 遍历算式数组，使用 eval() 计算每个算式的结果
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for expr in expressions:
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result = eval(expr) # 计算表达式的值
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results.append(result) # 将结果添加到结果数组中
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print(results)
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```
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> <span style="color: red; background: yellow; padding: 2px 5px; font-size: 22px;">作业2.1提交的内容</span>
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>
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> - 程序运行成功的截图，单独发送给组长
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# 词频统计
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## 需求
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- 编写一个词频统计程序，给定一个英文字符串，然后统计每个单词出现次数，并且存入一个字典中(暂不要求排序和截取)
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- 例如：`Python is a powerful programming language. Python is widely used for web development, data analysis, artificial intelligence, and scientific computing. Python is simple yet versatile.`
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- 输出：`{'python': 3, 'is': 3, 'a': 1, 'powerful': 1, 'programming': 1}`
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## 参考代码
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```python
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# 示例字符串
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text = """
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Python is a powerful programming language. Python is widely used for web development,
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data analysis, artificial intelligence, and scientific computing. Python is simple yet versatile.
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"""
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# 将字符串转换为小写，去掉标点符号，并按空格分割成单词
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words = text.lower()
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# 按照空格将单词分开
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word1 = words.split(" ")
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# 将单词前后的空格和换行符去除存入l2
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word2 = []
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for i in word1:
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i = i.strip(".")
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i = i.strip(",")
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i = i.strip()
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word2.append(i)
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# 手动统计单词频率
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word_count = {}
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for word in word2:
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if word in word_count:
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word_count[word] += 1
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else:
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word_count[word] = 1
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print(word_count)
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```
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## 扩展学习
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- 如果想要取排名前5的应该如何，需要大家提前预习后续的知识，发挥一下学习能力吧
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> <span style="color: red; background: yellow; padding: 2px 5px; font-size: 22px;">作业2.2提交的内容</span>
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>
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> - 程序运行成功的截图，单独发送给组长 |