[python] 文件复制/路径检测

import shutil

shutil.copytree(sourceResDir, dstResDir)
复制目录，olddir和newdir都只能是目录，且newdir必须不存在

文件的拷贝用shutil.copyfile(srcFilePath,dstFilePath)
oldfile和newfile都只能是文件

shutil.copy( src, dst) 复制一个文件，到一个文件或一个目录

import os

if not os.path.exist(path) 检测文件夹是否存在
os.mkdir() 如果不存在，创建文件夹 ,mkdir只能创建最后一层的文件夹
os.path.exists(no_exist_file.txt)判断文件，文件夹是否存在

import os 
#os.walk(path)遍历文件夹，没有返回值，直接循环调用
for root, dirs, files in os.walk(".", topdown=False):
    for name in files:
        print(os.path.join(root, name)) #文件名
    for name in dirs: # 子文件夹名
        print(os.path.join(root, name)) 

csv

读取

    with open(os.path.join('/hdd/NTU_RGBD', 'split_ntu_cs_frames.csv'), 'r') as fin:
        reader = csv.reader(fin)
        data = list(reader)
        root_path = '/hdd/NTU_RGBD/cs_frames'
        count = 0
        for item in data:
            print item
            origin_path = os.path.join(root_path,item[0],item[1],item[3]+'_rgb-'+item[4].zfill(4)+'.jpg')
            new_path = os.path.join('/hdd/NTU_RGBD/cs_one_frames',item[0],item[2],item[3]+'__rgb--00'+item[4]+'.jpg')
            shutil.copy(origin_path,new_path)
            count += 1
        print count

写入

    with open('split_ntu_cs_frames.csv', 'w') as fout:
        writer = csv.writer(fout)
        writer.writerows(frames)

write_row write_rows dict

			for train_sample in train:
				splits[i]['train'].extend(train_sample)
			for test_sample in test:
				splits[i]['test'].extend(test_sample)

	with open('setting_2.csv','w') as csvfile:
		header = ['test','train']
		writer = csv.DictWriter(csvfile,fieldnames =header)
		writer.writeheader()
		# for cross_val in splits:
		writer.writerows(splits) ，list中的每个元素都是字典

import csv

with open('names.csv', 'w') as csvfile:
    fieldnames = ['first_name', 'last_name']
    writer = csv.DictWriter(csvfile, fieldnames=fieldnames)

    writer.writeheader()
    writer.writerow({'first_name': 'Baked', 'last_name': 'Beans'})
    writer.writerow({'first_name': 'Lovely', 'last_name': 'Spam'})
    writer.writerow({'first_name': 'Wonderful', 'last_name': 'Spam'})
...
first_name,last_name
Baked,Beans
Lovely,Spam
Wonderful,Spam

>>> import csv
>>> with open('names.csv') as csvfile:
...     reader = csv.DictReader(csvfile)
...     for row in reader:
...         print(row['first_name'], row['last_name'])
...


Baked Beans
Lovely Spam
Wonderful Spam

读取的时候 ， reader是一个对象，不是一个列表，该怎么办？
如果用for循环取出的话，每一个row是一个字典。
字典中原来存储的array 变成了字符串，2-d array 变成了换行符+list+字符串

        with open(csv_name,'r') as csv_file:
            pred_true= csv.DictReader(csv_file)

            for row in pred_true:                
                y_pred_str = row['y_pred']
                y_pred_str = y_pred_str.strip('[]').split(' ') 
                for i in y_pred_str:  # 有些是空字符，有些还有换行符
                    if i != '':  
                        y_pred_list.append(eval(i))

glob

import glob
glob.glob()
glob给出的不是本机的绝对录路径，而是所给path的最深路径