如何使os.walk改变当前目录

Question

我的程序应该从给定的路径开始，然后通过它和它的子目录寻找jpegs并按捕获日期组织它们。我的程序在试图打开子目录中的文件时出现错误。它声明文件无法找到，当我开始打印当前目录时，我看到它不在子目录中。我的代码和错误如下。我怎样才能让os.walk变成下一个子目录？由于

import os 
import exifread 
from datetime import datetime 

class Image(object): 
    name = "" 
    dateTakem = "" 

    # The class "constructor" - It's actually an initializer 
    def __init__(self, name, dateTaken): 
     self.name = name 
     self.dateTaken = dateTaken 

def makeImage(name, dateTaken): 
    img = Image(name, dateTaken) 
    return img 

def formatDateTime(imageDt): 
    d = datetime.strptime(imageDt, '%Y:%m:%d %H:%M:%S') 
    dateStr = d.strftime('%Y:%m:%d') 
    return dateStr 

#path = raw_input("Please enter path name: ") 
path="/Users/Me/Pictures/Litmas"#For faster testing 
if not os.path.exists(path): 
    print ("Input path does not exist. Path is being created..") 
    try: 
     os.makedirs(path) 
    except (IOError, OSError) as exception: 
     print ("Path could not be created") 
    else: 
     print ("Success! Path has been created") 
os.chdir(path) 
count=0 
unique=0 
uniList=[] 
imgList=[] 
cwd = os.getcwd() 
print (cwd) 
for (dirname, dirs, files) in os.walk('.', topdown=False): 
    imgList[:]=[] 
    uniList[:]=[] 
    print (imgList) 
    print (uniList) 
    for filename in files: 
     #Checks if it is a JPEG 
     if filename.endswith('.jpg') or filename.endswith('.JPG') or filename.endswith('.JPEG') or filename.endswith('.jpeg'): 
      print ("\n"+filename) 
      #Adds 1 for every picture processed 
      count+=1 
      cwd = os.getcwd() 
      print (cwd) 
      #opens jpeg for exifread 
      f = open(filename, 'rb') 
      #Gets all the tags needed 
      tags = exifread.process_file(f, details=False) 
      #Goes through tags to find date captured 
      for tag in tags.keys(): 
       #Converts date object to string 
       dtStr=str(tags['EXIF DateTimeOriginal']) 
       #Strips time so it is just date 
       fDate = formatDateTime(dtStr) 
       fDate=fDate.replace(":","-") 
      print (fDate) 
      #Creates Image instance 
      newImg=makeImage(filename,fDate) 
      #Adds date to list for unique 
      uniList.append(fDate) 
      #Adds image instance to list for images 
      imgList.append(newImg) 
    uniList=list(set(uniList)) 
    unique+=len(uniList) 
    print ("Destination folders will be created with these filenames: ") 
    print (uniList) 
    #for folder in uniList: 
     #current=os.getcwd() 
     #newPath=current+"/"+folder 
     #try: 
      #os.makedirs(newPath) 
     #except (IOError, OSError) as exception: 
      #print ("Path could not be created") 
    #for image in imgList: 
     #filename=image.name 
     #dateDest=image.dateTaken 
     #current=os.getcwd() 
     #newDest=current+"/"+dateDest+"/"+filename 
     #currDest=current+"/"+filename 
     #os.rename(currDest, newDest) 

print ("Total JPEGs Processed: ") 
print(count) 
print ("Total Unique Dates Processed: ") 
print(unique) 

我的错误是：

Traceback (most recent call last): 

File "./Challenge.py", line 56, in <module> 

    f = open(filename, 'rb') 

IOError: [Errno 2] No such file or directory: 'DSC_0063.jpg' 

Answer 1

有一件事你可以做的是改变filename包括使用os.path.join像这样filename = os.path.join(dirname, filename)的目录。或者您可以在打开文件之前使用os.chdir(dirname)将当前目录更改为dirname。但是，在documentation中不推荐使用os.walk(".")时的后一种方法。因为它不会更改目录并假定用户不会。

注：如果你传递一个相对路径，不改变行走的复会的当前工作目录（）。 walk（）永远不会更改当前目录，并且假定其调用者不会。

Answer 2

os.walk返回元组路径：当前目录的路径，当前目录中的目录列表以及当前目录中的文件列表。

所以，你需要打开这些文件，这是什么：

f = open(os.path.join(dirname, filename), 'rb')