TypeError：调用函数时必须是 str，而不是 Python 3 中的 list

Question

我创建了一个函数来计算一个字母，例如字母 e。我的函数看起来与此类似：

 def count_letter(sentence, accents, case):

    lower_case_e = ['e']
    upper_case_E = ['E']
    accent_lower_case = ['é', 'ê', 'è']
    accent_upper_case = ['É', 'Ê', 'È']

    for character in sentence:#If statement for optional argument where ignore_accents == True and ignore_case == False.
        #This loop will count lower case and upper case e as differente letters but will treat accented characters the same.

        if accents == True and case == False:
            lower_case_count = sentence.count(lower_case_e)
            accent_lower_case_count = sentence.count(accent_lower_case)
            upper_case_count = sentence.count(upper_case_E)
            accent_upper_case_count = sentence.count(accent_upper_case)

            total_e_count = lower_case_count + accent_lower_case_count
            total_E_count = upper_case_count + accent_upper_case_count

            return {'Total number of lower case e in sentence ignoring accents':total_e_count, 'Total number of upper case E in sentence ignoring accents':total_E_count }

这个函数的要点是计算字母 e 的个数，并根据它是小写还是大写，或者它是否有重音符号，将字母加在一起。我创建了一个名为 sentence.txt 的文本文件，它看起来像这样：

 Testing if function can count letter e or E.

我已经使用以下代码阅读了该文件：

 # Reading the data from sentence.txt as a string
with open('sentence.txt', 'r') as Sentence_file:
    Sentence_string=Sentence_file.read().replace('\n', '')

阅读文件后，我尝试按以下方式调用该函数：

 count_letter(sentence, True, False)

但是，当我尝试运行它时，出现以下错误：

 TypeError: must be str, not list

任何人都知道可能出了什么问题？错误可能出在我阅读 txt.file 的方式上吗？任何建议将不胜感激！

完整的错误跟踪如下所示：

 ---------------------------------------------------------------------------
TypeError                                 Traceback (most recent call last)
<ipython-input-2-b171590ddd67> in <module>()
     29 with open('Test_Sentence1.txt', 'r') as Sentence1_file:
     30     Sentence1=Sentence1_file.read().replace('\n', '')
---> 31 count_letter_e(Sentence1, True, False)
     32

<ipython-input-2-b171590ddd67> in count_letter_e(sentence, accents, case)
     18         if accents == True and case == False:#If statement for optional argument where ignore_accents == True and ignore_case == False.
     19             #This loop will count lower case and upper case e as differente letters but will treat accented characters the same.
---> 20             lower_case_count = sentence.count(lower_case_e)#counting lower case e with no accent from the sentence
     21             accent_lower_case_count = sentence.count(accent_lower_case)#counting lower case e with accents from the sentence
     22             upper_case_count = sentence.count(upper_case_E)#counting upper case E with no accent from the sentence

TypeError: must be str, not list

原文由 adda.fuentes 发布，翻译遵循 CC BY-SA 4.0 许可协议

Answer 1

“ count() ”函数只接受一个字符串作为输入。例如：

 lower_case_count = 0
for lower_case_e_char in lower_case_e:
    lower_case_count += sentence.count(lower_case_e_char)
print(lower_case_count)

原文由 Forrest Abouelnasr 发布，翻译遵循 CC BY-SA 3.0 许可协议

Answer 2

在堆栈跟踪中指示的行中，您正在调用 .count() 方法并传入变量 lower_case_e 其值为 ['e'] .count() 方法需要一个字符串来计数，而不是多个值。例子：

 >>> testing = 'aba'
>>> testing.count('a')
2
>>> testing.count(['a'])
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
TypeError: expected a string or other character buffer object

因此，对于您要计算的具有多个字符（例如重音小写）的值，您需要循环并为每个字符串方法而不是整个列表添加 count() 的值一次。

原文由 MrName 发布，翻译遵循 CC BY-SA 3.0 许可协议