python让图片按照exif信息里的创建时间进行排序详解编程语言

我们经常会从不同的设备里取出照片，比如照相机，手机，iphone等等，操作系统记录的创建日期经常 会因为拷贝等原因变动，下面的代码可以给图片按照exif里的创建时间进行排序，非常有用。

import os 
import shutil 
import Image 
from PIL.ExifTags import TAGS 
 
def print_all_known_exif_tags(): 
    for k in sorted(TAGS): 
        print k, TAGS[k] 
  
def print_all_exif_tags(image): 
    try: 
        img = Image.open(image) 
    except Exception, e: 
        print image, "skipping due to", e 
    else: 
        xf = img._getexif() 
        for tag in xf: 
            print TAGS.get(tag), xf[tag] 
    finally: 
        print 'done' 
  
  
def get_minimum_creation_time(exif_data): 
    mtime = "?" 
    if 306 in exif_data and exif_data[306] < mtime: # 306 = DateTime 
        mtime = exif_data[306] 
    if 36867 in exif_data and exif_data[36867] < mtime: # 36867 = DateTimeOriginal 
        mtime = exif_data[36867] 
    if 36868 in exif_data and exif_data[36868] < mtime: # 36868 = DateTimeDigitized 
        mtime = exif_data[36868] 
    return mtime 
  
  
def get_creationdate_with_filename_as_dict(list_of_folders): 
    print "Processing all image files in:" 
  
    result = {} 
    for folder in list_of_folders: 
        print "- " + folder 
        counter = 0 
        for f in os.listdir(folder): 
            counter += 1 
            fullFileName = folder + "//" + f 
            try: 
                img = Image.open(fullFileName) 
            except Exception, e: 
                print "    Skipping '%s' due to exception: %s"%(f, e) 
                continue 
            mtime = get_minimum_creation_time(img._getexif()) 
            i = 0 
            while mtime+"_"*i in result: 
                i += 1 
            mtime = mtime+"_"*i 
            result[mtime] = fullFileName 
        print "  Found %s orignal files in %s."%(counter, folder) 
    print "Added total of %s to dictionary."%len(result) 
    return result 
  
  
def copy_from_image_dict_to_directory(image_dict, output_dir): 
    assert os.path.exists(output_dir) 
    for i,key in enumerate(sorted(image_dict)): 
        dummy, extension =  os.path.splitext(image_dict[key]) 
        new_file_name = key.replace(":", "-") + extension 
        output_file = output_dir + new_file_name 
        shutil.copy2(image_dict[key], output_file) 
    print "Copied %s files to %s"%(i+1, output_dir) 
  
  
if __name__=="__main__": 
    source_dir = "/var/tmp/images" 
    output_dir = "/var/tmp/output" 
  
    # obtain /var/tmp/images/iPhone, /var/tmp/images/CanonPowerShot, /var/tmp/images/Nikon1 
    list_of_folders = [source_dir + subfolder for subfolder in os.listdir(source_dir)] 
  
    all_files = get_creationdate_with_filename_as_dict(list_of_folders) 
    copy_from_image_dict_to_directory(all_files, output_dir)