为什么在错误消息中发现了换行符，而实际上没有换行符？

Question

此代码片段来自一个代码，旨在读取包含一百万个 pi 数字的文本文件，然后将所有六位连续数字提取到一个列表中（包括非唯一模式，以及 789012 等）。

with open('pi_million_digits.txt', 'r') as file:
    pi_file = file.read(100)

for x in range(len(pi_file)):
    if x > 1 and x < (len(pi_file) - 5):
        string_of_six = pi_file[x:x+6]    

    cons_check = []
    for digit in string_of_six:
            cons_check.append(int(digit)) 
    print(cons_check)

当我运行仅读取前 100 个字符的代码时，会出现此错误（文本文件中有不可见的

\n

，但第一个超过 100 个字符。）：

    ValueError                                Traceback (most recent call last)
    Cell In[84], line 20
         18         cons_check = []
         19         for digit in string_of_six:
    ---> 20                 cons_check.append(int(digit)) 
         21         print(cons_check)
         23 #     converts string into int and puts them in a list

    ValueError: invalid literal for int() with base 10: '\n'

尝试找出导致

ValueError: invalid literal for int() with base 10: '\n'

错误的原因。

以下是我尝试过的一些事情：

with open('pi_million_digits.txt', 'r') as file:
    pi_withn = file.read(50)
    pi_file = pi_withn.replace('\n', '')
    print(file.read(50))

使用replace来尝试替换 什么都没有给出同样的错误。

print(pi_withn)

和

print(pi_file)

两者都返回以下内容 - 同一行上的所有字符。

3.141592653589793238462643383279502884197169399375

还打开txt文件查看。前 100 个字符中没有换行符。

Answer 1

该问题可能是由于范围可变造成的。您在第一个

string_of_six

循环中定义

for

，但在第二个

for

循环中使用它，而无需在每次迭代中重新初始化它。这可能会导致变量保留较旧的值，可能包含先前读取的换行符。

试试这个：

with open('pi_million_digits.txt', 'r') as file:
    pi_file = file.read(100)

for x in range(len(pi_file)):
    string_of_six = ""  # Initialize in each iteration
    if x > 1 and x < (len(pi_file) - 5):
        string_of_six = pi_file[x:x+6]

    cons_check = []
    for digit in string_of_six:
        cons_check.append(int(digit))
    if cons_check:
        print(cons_check)

这可确保

string_of_six

在每次迭代开始时为空，从而防止先前迭代的任何结转。

使用

pi_million_digits.txt

输出：

[8, 9, 7, 9, 3, 2]
[9, 7, 9, 3, 2, 3]
[7, 9, 3, 2, 3, 8]
[9, 3, 2, 3, 8, 4]
[3, 2, 3, 8, 4, 6]
[2, 3, 8, 4, 6, 2]
[3, 8, 4, 6, 2, 6]
[8, 4, 6, 2, 6, 4]
[4, 6, 2, 6, 4, 3]
[6, 2, 6, 4, 3, 3]
[2, 6, 4, 3, 3, 8]
[6, 4, 3, 3, 8, 3]
[4, 3, 3, 8, 3, 2]
[3, 3, 8, 3, 2, 7]
[3, 8, 3, 2, 7, 9]
[8, 3, 2, 7, 9, 5]
[3, 2, 7, 9, 5, 0]
[2, 7, 9, 5, 0, 2]
[7, 9, 5, 0, 2, 8]
[9, 5, 0, 2, 8, 8]
[5, 0, 2, 8, 8, 4]
[0, 2, 8, 8, 4, 1]
[2, 8, 8, 4, 1, 9]
[8, 8, 4, 1, 9, 7]
[8, 4, 1, 9, 7, 1]
[4, 1, 9, 7, 1, 6]
[1, 9, 7, 1, 6, 9]
[9, 7, 1, 6, 9, 3]
[7, 1, 6, 9, 3, 9]
[1, 6, 9, 3, 9, 9]
[6, 9, 3, 9, 9, 3]
[9, 3, 9, 9, 3, 7]
[3, 9, 9, 3, 7, 5]
[9, 9, 3, 7, 5, 1]
[9, 3, 7, 5, 1, 0]
[3, 7, 5, 1, 0, 5]
[7, 5, 1, 0, 5, 8]
[5, 1, 0, 5, 8, 2]
[1, 0, 5, 8, 2, 0]
[0, 5, 8, 2, 0, 9]
[5, 8, 2, 0, 9, 7]
[8, 2, 0, 9, 7, 4]
[2, 0, 9, 7, 4, 9]
[0, 9, 7, 4, 9, 4]
[9, 7, 4, 9, 4, 4]
[7, 4, 9, 4, 4, 5]
[4, 9, 4, 4, 5, 9]
[9, 4, 4, 5, 9, 2]
[4, 4, 5, 9, 2, 3]
[4, 5, 9, 2, 3, 0]
[5, 9, 2, 3, 0, 7]
[9, 2, 3, 0, 7, 8]
[2, 3, 0, 7, 8, 1]
[3, 0, 7, 8, 1, 6]
[0, 7, 8, 1, 6, 4]
[7, 8, 1, 6, 4, 0]
[8, 1, 6, 4, 0, 6]
[1, 6, 4, 0, 6, 2]
[6, 4, 0, 6, 2, 8]
[4, 0, 6, 2, 8, 6]
[0, 6, 2, 8, 6, 2]
[6, 2, 8, 6, 2, 0]
[2, 8, 6, 2, 0, 8]
[8, 6, 2, 0, 8, 9]
[6, 2, 0, 8, 9, 9]
[2, 0, 8, 9, 9, 8]
[0, 8, 9, 9, 8, 6]
[8, 9, 9, 8, 6, 2]
[9, 9, 8, 6, 2, 8]
[9, 8, 6, 2, 8, 0]
[8, 6, 2, 8, 0, 3]
[6, 2, 8, 0, 3, 4]
[2, 8, 0, 3, 4, 8]
[8, 0, 3, 4, 8, 2]
[0, 3, 4, 8, 2, 5]
[3, 4, 8, 2, 5, 3]
[4, 8, 2, 5, 3, 4]
[8, 2, 5, 3, 4, 2]
[2, 5, 3, 4, 2, 1]
[5, 3, 4, 2, 1, 1]
[3, 4, 2, 1, 1, 7]
[4, 2, 1, 1, 7, 0]
[2, 1, 1, 7, 0, 6]