python - 在Python中迭代大型文件目录系统，获取太多值而无法解压

Question

我正在 python 中迭代一个非常大的文件和目录系统。我从基本目录开始，并且我知道该目录的深度不超过基本目录的 1 个文件夹。我正在尝试使用如下代码读出 base_directories 子文件夹中每个文件的第二行:

a_list = []
  for dir, files in os.walk(base_directory):
    for file in files:
      f=open(file, 'r')
      for line in f:
        #reads in the second line
        if line==1:
          a_list.append(line)
          break
      f.close() 

但是我得到了太多的值，无法在“for dir, file in os.walk(base_directory)”这一行专门解压，谢谢您的帮助!

Answer 1

您应该解压一个三元组

walk(top, topdown=True, onerror=None, followlinks=False)    Directory tree generator.    For each directory in the directory tree rooted at top (including top    itself, but excluding '.' and '..'), yields a 3-tuple        dirpath, dirnames, filenames

eg.

for dir, dirnames, files in os.walk(base_directory):

此外，这也行不通。 line 是一个适合初学者的字符串

  for line in f:
    #reads in the second line
    if line==1:
      a_list.append(line)
      break

你可以把它改成这样

  for i, line in enumerate(f):
    #reads in the second line
    if i==1:
      a_list.append(line)
      break

但我认为这是一个更简单的方法

  import os
  a_list = []
  for dirpath, dirnames, files in os.walk(base_directory):
    for file in files:
      with open(os.path.join(dirpath, file), 'r') as f:
        next(f)                 # skip the first line
        a_list.append(next(f))  # store the second line