下面是我用来简化文件I/O的Python（3）助手库类：

import os

# handle files using a callback method, prevents repetition
def _FileIO__file_handler(file_path, mode, callback = lambda f: None):
  f = open(file_path, mode)
  try:
    return callback(f)
  except Exception as e:
    raise IOError("Failed to %s file" % ["write to", "read from"][mode.lower() in "r rb r+".split(" ")])
  finally:
    f.close()


class FileIO:
  # return the contents of a file
  def read(file_path, mode = "r"):
    return __file_handler(file_path, mode, lambda rf: rf.read())

  # get the lines of a file
  def lines(file_path, mode = "r", filter_fn = lambda line: len(line) > 0):
    return [line for line in FileIO.read(file_path, mode).strip().split("\n") if filter_fn(line)]

  # create or update a file (NOTE: can also be used to replace a file's original content)
  def write(file_path, new_content, mode = "w"):
    return __file_handler(file_path, mode, lambda wf: wf.write(new_content))

  # delete a file (if it exists)
  def delete(file_path):
    return os.remove() if os.path.isfile(file_path) else None

然后使用FileIO.lines函数，如下所示：

file_ext_lines = FileIO.lines("./path/to/file.ext"):
for i, line in enumerate(file_ext_lines):
  print("Line {}: {}".format(i + 1, line))

请记住，mode（默认为“r”）和filter_fn（默认为检查空行）参数是可选的。

您甚至可以删除read、write和delete方法，只保留FileIO.line，甚至将其转换为一个单独的方法read_lines。

这段代码将把整个文件读入内存，并删除每行末尾的所有空白字符（换行符和空格）：

with open(filename) as file:
    lines = [line.rstrip() for line in file]

如果您正在处理一个大文件，那么您应该逐行读取并处理它：

with open(filename) as file:
    for line in file:
        print(line.rstrip())

在Python 3.8及以上版本中，可以使用while循环和walrus运算符，如下所示：

with open(filename) as file:
    while (line := file.readline().rstrip()):
        print(line)

根据您计划对文件执行的操作以及文件的编码方式，您可能还需要手动设置访问模式和字符编码：

with open(filename, 'r', encoding='UTF-8') as file:
    while (line := file.readline().rstrip()):
        print(line)

参见输入和输出：

with open('filename') as f:
    lines = f.readlines()

或者去掉换行符：

with open('filename') as f:
    lines = [line.rstrip('\n') for line in f]

具有文本文件内容：

line 1
line 2
line 3

我们可以在上面txt的同一目录中使用此Python脚本

>>> with open("myfile.txt", encoding="utf-8") as file:
...     x = [l.rstrip("\n") for l in file]
>>> x
['line 1','line 2','line 3']

使用追加：

x = []
with open("myfile.txt") as file:
    for l in file:
        x.append(l.strip())

Or:

>>> x = open("myfile.txt").read().splitlines()
>>> x
['line 1', 'line 2', 'line 3']

Or:

>>> x = open("myfile.txt").readlines()
>>> x
['linea 1\n', 'line 2\n', 'line 3\n']

Or:

def print_output(lines_in_textfile):
    print("lines_in_textfile =", lines_in_textfile)

y = [x.rstrip() for x in open("001.txt")]
print_output(y)

with open('001.txt', 'r', encoding='utf-8') as file:
    file = file.read().splitlines()
    print_output(file)

with open('001.txt', 'r', encoding='utf-8') as file:
    file = [x.rstrip("\n") for x in file]
    print_output(file)

输出：

lines_in_textfile = ['line 1', 'line 2', 'line 3']
lines_in_textfile = ['line 1', 'line 2', 'line 3']
lines_in_textfile = ['line 1', 'line 2', 'line 3']

如果您想从命令行或stdin读取文件，也可以使用fileinput模块：

# reader.py
import fileinput

content = []
for line in fileinput.input():
    content.append(line.strip())

fileinput.close()

将文件传递给它，如下所示：

$ python reader.py textfile.txt 

在此处阅读更多信息：http://docs.python.org/2/library/fileinput.html

这比必要的更明确，但可以做到你想要的。

with open("file.txt") as file_in:
    lines = []
    for line in file_in:
        lines.append(line)