Python 我能识别小写和大写字母，并把它们放在字典里。我需要将大小写值连接在一起

我需要知道一个字符显示多少次，并将结果保存到字典中。例如：

{“e”：8，“s”：7}

表示“e”显示8次，“s”显示7次。我必须使大小写值相同

我设法找出了每个角色的显示次数。我很难让大小写字母在一起而不是分开

counting_symbols = {}
for letter in "Cryptography is the practice and study of techniques" \
              " for secure communication in the presence of third parties" \
              " called adversaries. More generally, cryptography is about" \
              " constructing and analyzing protocols that prevent third" \
              " parties or the public from reading private messages; various " \
              "aspects in information security such as data confidentiality, " \
              "data integrity, authentication, and non-repudiation are central " \
              "to modern cryptography. Modern cryptography exists at the" \
              " intersection of the disciplines of mathematics, computer science, " \
              "electrical engineering, communication science, and physics. Applications " \
              "of cryptography include electronic commerce, chip-based payment cards, " \
              "digital currencies, computer passwords, and military communications.":
    counting_symbols[letter] = counting_symbols.get(letter, 0) + 1



print(counting_symbols)

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这使得大写字母和小写字母分开。有人能帮你把它们连在一起吗？

你计算它们的方法可以更具体一些。仅给出一个伪代码示例：

if(letter == ('S' or 's')):
  num_s = num_s+1

---

例如，您可以在函数中为每个字母复制并粘贴此行。最后，你可以返回这些数字。我希望你能理解我算法的要点。您可以通过多种方式实现它，我的算法非常具体。

您只需添加1行代码即可将字母转换为小写：

counting_symbols = {}
for letter in "Cryptography is the practice and study of techniques" \
          " for secure communication in the presence of third parties" \
          " called adversaries. More generally, cryptography is about" \
          " constructing and analyzing protocols that prevent third" \
          " parties or the public from reading private messages; various " \
          "aspects in information security such as data confidentiality, " \
          "data integrity, authentication, and non-repudiation are central " \
          "to modern cryptography. Modern cryptography exists at the" \
          " intersection of the disciplines of mathematics, computer science, " \
          "electrical engineering, communication science, and physics. Applications " \
          "of cryptography include electronic commerce, chip-based payment cards, " \
          "digital currencies, computer passwords, and military communications.":
letter = str.lower(letter)
counting_symbols[letter] = counting_symbols.get(letter, 0) + 1

print(counting_symbols)

---

您可以使用lower（）函数降低所有字符，并将其保存到另一个变量中

使用collections库中的Counter类也是一个很好的实践。计数器对象自动计算一个或多个字符串中的字符数，并将数据保存在字典中

text = "Cryptography is the practice and study of techniques"
lower_chars = text.lower()

from collections import Counter
counter = Counter(lower_chars)
print(counter)

---

为什么不先将整个字符串小写或大写？没有测试，而是尝试

计数\u符号[letter.lower（）]=计数\u符号.get（letter.lower（），0）+1

使用

letter=letter.lower（）

或

letter=letter.upper（）

在更新计数之前。因此这不是一个很好的答案，因为它需要复制和粘贴大量代码。处理全大写或全小写是更好的做法，因为它更简洁，更易于作为代码管理。一般来说，所有较低的是公约（特别是从问题来看）