将列表写入文件txt（utf-8）

Question

I tried to write a list to txt file with the encoding utf-8 without BOM. But have a problem is: If i create that file with utf-8 withou BOM encoding:

  ポ
  1
  田
  11
  直
  11
  子
  11

and use my function to read it to a list:

import codecs
def file_to_list(file_name):
    results = []
    f = codecs.open(file_name, encoding='utf-8')
    for line in f:
        results.append(line.replace('\r\n', ''))
    return results
list_1 = file_to_list('test_read.txt')
print(list_1)

I got the ok result : ['ポ', '1', '田', '11', '直', '11', '子', '11'] But after this i using another function to write back to file and read that file again, a problem appear:

def list_to_file(file_name, thelist):
    f = codecs.open(file_name, "w", encoding='utf-8')
    for item in thelist:
        f.write("%s\n" % item)
list_to_file('test_read.txt', list_1)
list_2 = file_to_list('test_read.txt')
print(list_2)

the return of print is : ['ポ\\n', '1\\n', '田\\n', '11\\n', '直\\n', '11\\n', '子\\n', '11\\n'] So, what wrong to make '\\n' ?

Answer 1

You should not be replacing trailing whitespaces/new line characters as they may vary across platforms. You should strip them. More so, you're writing to the file with only \\n , but your function expects \\r\\n .

In your file_to_list function, replace:

results.append(line.replace('\r\n', ''))

with

results.append(line.rstrip())

---

See:

>>> 'some line\n'.replace('\r\n', '')
'some line\n'