在Python的字典中分别计算大小写

我试着做以下练习： 想想这句话“吉姆很快意识到漂亮的礼服是昂贵的”。创建一个字典，用包含句子中每个唯一字母的键和包含每个字母在此句子中使用次数的值来计算字母数。在字典中分别计算大写字母和小写字母

下面是我的代码，我认为它在做练习要求的事情，但出于某种原因，它仍然说我做得不对。有什么想法吗

sentence = 'Jim quickly realized that the beautiful gowns are expensive'
count_letters = {}
cnt_lowercase = 0
cnt_uppercase = 0
#write your code here!
for c in sentence:
    if c.islower():
        if (c in count_letters) == False:
            count_letters[c]={c:sentence.count(c)}
            cnt_lowercase += 1
    if c.isupper():
        if (c in count_letters) == False:
            count_letters[c]={c:sentence.count(c)}
            cnt_uppercase += 1
print(str(cnt_lowercase))
print(str(cnt_uppercase))
print(count_letters)

---

问题在于，

count\u letters

是一个字典，其中键是字母，值是带有该字母计数的字典，在练习中要求您计算

由每个字母在本文件中使用的次数组成的值 判决

您的代码：

sentence = 'Jim quickly realized that the beautiful gowns are expensive'
count_letters = {}
cnt_lowercase = 0
cnt_uppercase = 0
for c in sentence:
    if c.islower():
        if (c in count_letters) == False:
            count_letters[c]={c:sentence.count(c)}
            cnt_lowercase += 1
    if c.isupper():
        if (c in count_letters) == False:
            count_letters[c]={c:sentence.count(c)}
            cnt_uppercase += 1
print(count_letters)

输出

{'u': {'u': 3}, 'g': {'g': 1}, 'q': {'q': 1}, 'l': {'l': 3}, 'o': {'o': 1}, 'm': {'m': 1}, 'f': {'f': 1}, 'k': {'k': 1}, 'z': {'z': 1}, 'w': {'w': 1}, 'a': {'a': 4}, 'n': {'n': 2}, 'c': {'c': 1}, 'y': {'y': 1}, 'r': {'r': 2}, 'b': {'b': 1}, 'h': {'h': 2}, 'd': {'d': 1}, 'e': {'e': 8}, 'i': {'i': 5}, 'v': {'v': 1}, 'p': {'p': 1}, 's': {'s': 2}, 'x': {'x': 1}, 'J': {'J': 1}, 't': {'t': 4}}

例如，

'u'

的值是

{'u'：3}

。您可以通过添加以下行来修复它：

count_letters = { k : v[k] for k, v in count_letters.items()}
print(count_letters)

输出（使用新行）

解释

添加的行称为字典理解。相当于：

d = {}
for k, v in count_letters.items():
    d[k] = v[k]
count_letters = d

---

您的词典嵌套了其他不应该是这种情况的词典

例如

应该是公正的

{'u': 3}

我简化了您的代码，现在应该可以使用了：

sentence = 'Jim quickly realized that the beautiful gowns are expensive'
count_letters = {}
cnt_lowercase = 0
cnt_uppercase = 0

for c in sentence:
    if (c in count_letters):
        count_letters[c] += 1
    else:
        count_letters[c] = 1

cnt_lowercase = len([i for i in count_letters.keys() if i.islower()])
cnt_uppercase = len([i for i in count_letters.keys() if i.isupper()])

print(count_letters)
print(cnt_lowercase)
print(cnt_uppercase)

---

您不应该有一个字典字典，而应该有一个直接返回字符计数的字典，这意味着当您键入

count_字母['J']

时，例如，您会得到1

在您的代码中，当我键入

计数字母['J']

时，我得到

{'J'：1}

作为输出

下面是我将如何编写此代码：

sentence = 'Jim quickly realized that the beautiful gowns are expensive'

count_letters = {}
cnt_lowercase = 0
cnt_uppercase = 0

# iterate over all chars in the sentence string
for char in sentence:
    # check if the char is lowercase
    if char.islower():
        cnt_lowercase += 1
    # check if the char is upper case
    elif char.isupper():
        cnt_uppercase += 1

    # count occurrence of each char in sentence string
    b = count_letters.get(char, 0)
    count_letters[char] = b + 1


# check the output
print(count_letters)

您可以得到以下输出：

{'J': 1, 'i': 5, 'm': 1, ' ': 8, 'q': 1, 'u': 3, 'c': 1, 'k': 1, 'l': 3, 'y': 1, 'r': 2, 'e': 8, 'a': 4, 'z': 1, 'd': 1, 't': 4, 'h': 2, 'b': 1, 'f': 1, 'g': 1, 'o': 1, 'w': 1, 'n': 2, 's': 2, 'x': 1, 'p': 1, 'v': 1}

---

将缓存构建和计数逻辑委托给不同的功能：

   def build_cache(sentence):
        char_to_count_cache = {}
        for ch in sentence:
            if ch.isalnum():
                char_to_count_cache[ch] = char_to_count_cache.get(ch, 0) + 1

        return char_to_count_cache

    def get_upper_and_lower_counts(char_to_count_cache):
        num_lower_letters, num_upper_letters = 0, 0
        for k in char_to_count_cache:
            if k.islower():
                num_lower_letters += 1
            else:
                num_upper_letters += 1

        return num_lower_letters, num_upper_letters

司机：

sentence = 'Jim quickly realized that the beautiful gowns are expensive'
char_to_count_cache = build_cache(sentence)
num_lower_letters, num_upper_letters = get_upper_and_lower_counts(char_to_count_cache)

total_letters = len(char_to_count_cache)

print total_letters
print num_lower_letters
print num_upper_letters

输出：

26 
25 
1 

您可以使用调用来完成此任务

 alphabet = 'abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ'
 sentence = 'Jim quickly realized that the beautiful gowns are expensive'
 counts = dict([[letter, sentence.count(letter)] for letter in set(sentence) if letter in alphabet]) 

---

这是我对清单理解的建议

注：在表格中分别计算大写字母和小写字母 字典

---

这就是上述问题的解决方案。您可以根据需要进行修改

alphabet = 'abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ'
sentence = 'Jim quickly realized that the beautiful gowns are expensive'
count_letters = dict()

for letter in sentence:
    if letter in alphabet:
        if letter in count_letters.keys():
            count_letters[letter] += 1
        else:
            count_letters[letter] = 1

print(list(count_letters.values())[2])
print(list(count_letters.values())[7])

---

我能得到否决票的理由吗？如果有需要解决的问题，我很想改进。。。

26 
25 
1 

 alphabet = 'abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ'
 sentence = 'Jim quickly realized that the beautiful gowns are expensive'
 counts = dict([[letter, sentence.count(letter)] for letter in set(sentence) if letter in alphabet]) 

sentence = 'Jim quickly realized that the beautiful gowns are expensive'

alphabet = 'abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ'

count_letters_upper = ([[letter, sentence.count(letter)] for letter in set(sentence) if letter in alphabet if letter.isupper()])

count_letters_lower = ([[letter, sentence.count(letter)] for letter in set(sentence) if letter in alphabet if letter.islower()])

alphabet = 'abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ'
sentence = 'Jim quickly realized that the beautiful gowns are expensive'
count_letters = dict()

for letter in sentence:
    if letter in alphabet:
        if letter in count_letters.keys():
            count_letters[letter] += 1
        else:
            count_letters[letter] = 1

print(list(count_letters.values())[2])
print(list(count_letters.values())[7])