循环不插入换行符当使用zip_longest Python 3

Question

我正在写一个简单的文本比较工具。它接受两个文本文件——一个模板和一个目标——并使用两个for循环比较每行中的每个字符。任何差异都用Unicode完整块符号(u2588)突出显示。在目标行比模板长的情况下，我使用itertools.zip_longest用填充值填充不存在的字符。

from itertools import zip_longest
def compare(filename1, filename2):

file1 = open(filename1, "r")
file2 = open(filename2, "r")

for line1, line2 in zip_longest(file1, file2):

for char1, char2 in zip_longest(line1, line2, fillvalue=None):

if char1 == char2:
print(char2, end='')

elif char1 == None:
print('u2588', end='')
compare('template.txt', 'target.txt')

Template file:        Target file:
First line            First lineXX
Second line           Second line
Third line            Third line

然而，这似乎会扰乱Python的自动换行位置。当一行以这样的填充值结束时，不会生成换行符，给出如下结果:

First line██Second line
Third line

代替:

First line██
Second line
Third line

在重写脚本以使用.append和.join(不显示以保持简短)之后，问题仍然存在，尽管它允许我突出显示问题:

Result when both files are identical:
['F', 'i', 'r', 's', 't', ' ', 'l', 'i', 'n', 'e', 'n']
First line
['S', 'e', 'c', 'o', 'n', 'd', ' ', 'l', 'i', 'n', 'e', 'n']
Second line
['T', 'h', 'i', 'r', 'd', ' ', 'l', 'i', 'n', 'e']
Third line
Result when first line of target file has two more characters:
['F', 'i', 'r', 's', 't', ' ', 'l', 'i', 'n', 'e', '█', '█']
First line██['S', 'e', 'c', 'o', 'n', 'd', ' ', 'l', 'i', 'n', 'e', 'n']
Second line
['T', 'h', 'i', 'r', 'd', ' ', 'l', 'i', 'n', 'e']
Third line

如您所见，如果行长度相同，Python会自动添加一个换行符n，但只要涉及到zip_longest，列表中的最后一个字符就是块，而不是换行符。为什么会发生这种情况?

Answer 1

在比较字符之前去掉行并在每行之间打印新行:

from itertools import zip_longest
def compare(filename1, filename2):

file1 = open(filename1, "r")
file2 = open(filename2, "r")

for line1, line2 in zip_longest(file1, file2):
line1, line2 = line1.strip(), line2.strip()  # <- HERE
for char1, char2 in zip_longest(line1, line2, fillvalue=None):

if char1 == char2:
print(char2, end='')
elif char1 == None:
print('u2588', end='')
print()  # <- HERE
compare('template.txt', 'target.txt')