需要用到 os 模块和 sys 模块
import os print(__file__)# 输出相对路径 print(os.path.abspath(__file__)) #输出绝对路径 # D:\Project\180410gentic\Rahul_Genetic_Program\analysis\test.py print os.path.dirname(os.path.abspath(__file__)) #返回目录名不要文件名 # D:\Project\180410gentic\Rahul_Genetic_Program\analysis import sys BASE_DIR = os.path.dirname(os.path.abspath(__file__)) # 设为基本路径 sys.path.append(BASE_DIR) #将路径添加环境变量
os.walk目录遍历
os.walk(top, topdown=True, onerror=None, followlinks=False)
- top是要遍历的目录。
- topdown是代表要从上而下遍历还是从下往上遍历。
- onerror可以用来设置当遍历出现错误的处理函数(该函数接受一个OSError的实例作为参数)，设置为空则不作处理。
- followlinks表示是否要跟随目录下的链接去继续遍历，要注意的是，os.walk不会记录已经遍历的目录，所以跟随链接遍历的话有可能一直循环调用下去。
os.walk返回的是一个3个元素的元组 (root, dirs, files) ，分别表示遍历的路径名，该路径下的目录列表和该路径下文件列表。注意目录列表和文件列表不是具体路径，需要具体路径(从root开始的路径)的话可以用 os.path.join(root,dir)和 os.path.join(root,dir) 。
├── a.py
├── b.py
├── c.py
├── dir1
│ ├── dir4
│ │ ├── g.py
│ │ └── h.py
│ ├── dirx
│ │ ├── diry
│ │ │ └── k.py
│ │ └── z.py
│ ├── e.py
│ ├── f.py
│ └── g.py
├── dir2
│ ├── dira
│ │ └── dirb
│ │ └── dirc
│ │ └── aha.py
│ ├── k.py
│ ├── l.py
│ └── m.py
└── dir3
├── dir5
│ └── z.py
├── x.py
└── y.py
10 directories, 17 files
测试topdown
当我用 os.walk 遍历这个目录时，程序和输出如下:
import os
path = '/Users/nisen/Projects/python_advanced_class/test/test_os_walk'
for root, dirs, files in os.walk(path, True):
print('root: %s' % root)
print('dirs: %s' % dirs)
print('files: %s' % files)
print (' ')
结果如下，从root的路径可以看出遍历是自上而下的：
root: /Users/nisen/Projects/python_advanced_class/test/test_os_walk dirs: ['dir1', 'dir2', 'dir3'] files: ['a.py', 'b.py', 'c.py'] root: /Users/nisen/Projects/python_advanced_class/test/test_os_walk/dir1 dirs: ['dir4', 'dirx'] files: ['e.py', 'f.py', 'g.py'] root: /Users/nisen/Projects/python_advanced_class/test/test_os_walk/dir1/dir4 dirs: [] files: ['g.py', 'h.py'] root: /Users/nisen/Projects/python_advanced_class/test/test_os_walk/dir1/dirx dirs: ['diry'] files: ['z.py'] root: /Users/nisen/Projects/python_advanced_class/test/test_os_walk/dir1/dirx/diry dirs: [] files: ['k.py'] root: /Users/nisen/Projects/python_advanced_class/test/test_os_walk/dir2 dirs: ['dira'] files: ['k.py', 'l.py', 'm.py'] root: /Users/nisen/Projects/python_advanced_class/test/test_os_walk/dir2/dira dirs: ['dirb'] files: [] root: /Users/nisen/Projects/python_advanced_class/test/test_os_walk/dir2/dira/dirb dirs: ['dirc'] files: [] root: /Users/nisen/Projects/python_advanced_class/test/test_os_walk/dir2/dira/dirb/dirc dirs: [] files: ['aha.py'] root: /Users/nisen/Projects/python_advanced_class/test/test_os_walk/dir3 dirs: ['dir5'] files: ['x.py', 'y.py'] root: /Users/nisen/Projects/python_advanced_class/test/test_os_walk/dir3/dir5 dirs: [] files: ['z.py']
而当设置os.walk的topdown为False时，结果如下, 可以看出他是自上而下遍历的：
root: /Users/nisen/Projects/python_advanced_class/test/test_os_walk/dir1/dir4 dirs: [] files: ['g.py', 'h.py'] root: /Users/nisen/Projects/python_advanced_class/test/test_os_walk/dir1/dirx/diry dirs: [] files: ['k.py'] root: /Users/nisen/Projects/python_advanced_class/test/test_os_walk/dir1/dirx dirs: ['diry'] files: ['z.py'] root: /Users/nisen/Projects/python_advanced_class/test/test_os_walk/dir1 dirs: ['dir4', 'dirx'] files: ['e.py', 'f.py', 'g.py'] root: /Users/nisen/Projects/python_advanced_class/test/test_os_walk/dir2/dira/dirb/dirc dirs: [] files: ['aha.py'] root: /Users/nisen/Projects/python_advanced_class/test/test_os_walk/dir2/dira/dirb dirs: ['dirc'] files: [] root: /Users/nisen/Projects/python_advanced_class/test/test_os_walk/dir2/dira dirs: ['dirb'] files: [] root: /Users/nisen/Projects/python_advanced_class/test/test_os_walk/dir2 dirs: ['dira'] files: ['k.py', 'l.py', 'm.py'] root: /Users/nisen/Projects/python_advanced_class/test/test_os_walk/dir3/dir5 dirs: [] files: ['z.py'] root: /Users/nisen/Projects/python_advanced_class/test/test_os_walk/dir3 dirs: ['dir5'] files: ['x.py', 'y.py'] root: /Users/nisen/Projects/python_advanced_class/test/test_os_walk dirs: ['dir1', 'dir2', 'dir3'] files: ['a.py', 'b.py', 'c.py']
os.path.join()函数用于路径拼接文件路径
-
会从第一个以”/”开头的参数开始拼接，之前的参数全部丢弃。
-
以上一种情况为先。在上一种情况确保情况下，若出现”./”开头的参数，会从”./”开头的参数的上一个参数开始拼接
import os
print("1:",os.path.join('aaaa','/bbbb','ccccc.txt'))
print("2:",os.path.join('/aaaa','/bbbb','/ccccc.txt'))
print("3:",os.path.join('aaaa','./bbb','ccccc.txt'))
# 1: /bbbb\ccccc.txt
# 2: /ccccc.txt
# 3: aaaa\./bbb\ccccc.txt