译（二十九）-Python按行读取文件并存进列表

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如何按行读取文件并存进列表？

• Julie Raswick asked:

  • Python如何读取一个文件的每一行，并将其存进列表里？
  • 按行读取，然后追加到列表末尾。

• Answers:

  • SilentGhost - vote: 2450

  • 下面的代码可以读取文件至内存，并且移除每行的空白字符（换行符与空格）：

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

  • 如果是读取大文件，最后按行读取并处理：

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

  • Python3.8可以用带海象运算符的while循环（译者注：:=长得像海象，所以这么叫，文档里说的）：

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

  • 根据文件的处理需求与编码方式来设置不同的读取方式与编码方式：

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

  • Felix Kling - vote: 1108

  • 见输入与输出

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

  • 或者去除换行符：

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

  • robert - vote: 667

  • 虽然这不简洁，但的确如要求一般：

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

How to read a file line-by-line into a list?

• Julie Raswick asked:

  • How do I read every line of a file in Python and store each line as an element in a list?
    Python如何读取一个文件的每一行，并将其存进列表里？
  • I want to read the file line by line and append each line to the end of the list.
    按行读取，然后追加到列表末尾。

• Answers:

  • SilentGhost - vote: 2450

  • This code will read the entire file into memory and remove all whitespace characters (newlines and spaces) from the end of each line:
    下面的代码可以读取文件至内存，并且移除每行的空白字符（换行符与空格）：

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

  • If you\'re working with a large file, then you should instead read and process it line-by-line:
    如果是读取大文件，最后按行读取并处理：

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

  • In Python 3.8 and up you can use a while loop with the walrus operator like so:
    Python3.8可以用带海象运算符的while循环（译者注：:=长得像海象，所以这么叫，文档里说的）：

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

  • Depending on what you plan to do with your file and how it was encoded, you may also want to manually set the access mode and character encoding:
    根据文件的处理需求与编码方式来设置不同的读取方式与编码方式：

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

  • Felix Kling - vote: 1108

  • See Input and Ouput:
    见输入与输出

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

  • or with stripping the newline character:
    或者去除换行符：

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

  • robert - vote: 667

  • This is more explicit than necessary, but does what you want.
    虽然这不简洁，但的确如要求一般：

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