# OS系統操作
###### tags: `python語法`
## 1.更改文件檔名 os.rename

os.rename(“list.txt”,”123.txt”)
os.rename(原檔名,新檔名)

#### 1.1 批量修改檔名

# 在指定path路徑下，將該層檔案及資料夾名稱前加上字串     
    for fname in os.listdir(path):
        new_fname = " "+fname
        os.rename(os.path.join(path, fname), os.path.join(path, new_fname))

#### 1.2 顯示檔名

    # 顯示指定路徑下的所有檔案及資料夾名稱
    for fd in os.listdir(path):
        full_path=os.path.join(path,fd)
        if os.path.isdir(full_path):
            print('資料夾:',full_path)
            find_dir(full_path)
        else:
            print('檔案:',full_path)

## 2.刪除檔案 os.remove

os.remove(“list.txt”)

## 3.建立資料夾 os.mkdir

import os
os.mkdir(“資料夾名稱”)
#檢查目錄是否存在，若無，則建立資料夾
dir='myDir'
if not os.path.exists(dir):
    os.mkdir(dir)
else:
    print(dir + '已經建立！')

#### 3.1建立多層資料夾os.mkdirs()

os.makedirs("./music/subdir") 
os.makedirs("./music/a/b") 
os.makedirs("./music/a/b", exist_ok =True)

## 4.獲取當前目錄 os.getcwd()

os.getcwd()

## 5.返回上層目錄 os.chdir(“../”)

os.chdir(“../”)

## 6.獲取目錄列表 os.listdir(“./”)

os.listdir(“./”)

## 7.刪除資料夾 os.rmdir( )

os.rmdir(“資料夾名稱")

## 8.批量修改檔名

import os
file_name = “txt文件”
file_names = os.listdir(file_name)
os.chdir(file_name)
for name in file_names :
    os.rename(name,"要添加的文字"+ name)

## 9.列出所有資料夾與檔案

import os
path='f:\\python'
def find_dir(dir):
    fds=os.listdir(dir)
    for fd in fds:
        full_path=os.path.join(dir,fd)
        if os.path.isdir(full_path):
            print('資料夾:',full_path)
            find_dir(full_path)
        else:
            print('檔案:',full_path)
find_dir(path)

## 10.列出指定結尾檔案

import os
path='f:\\python'
for root,dirs,files in os.walk(path): #root 路徑; dirs 資料夾名稱; files 檔案名稱
    for file in files:
        if file.endswith('.py'):             #py為結尾
            print(os.path.join(root,file))

## 11.使用os.walk列出所有JPG與PNG檔案

import fnmatch, os
path='f:\\python'
exts = ['*.jpg','*.jpeg','*.png']
mathches = []
for root, dirs, files in os.walk(path):
    for ext in exts:
        for file in fnmatch.filter(files,ext):
            matches.append(os.path.join(root, file))
for image in matches:
    print(image)

#### os.walk

## 定義讀檔路徑function

def get_filepaths(directory):
    """
    This function will generate the file names in a directory 
    tree by walking the tree either top-down or bottom-up. For each 
    directory in the tree rooted at directory top (including top itself), 
    it yields a 3-tuple (dirpath, dirnames, filenames).
    """
    file_paths = []  # List which will store all of the full filepaths.

    # Walk the tree.

    for root, directories, files in os.walk(directory): #root 路徑; directories 資料夾名稱; files 檔案名稱

        for filename in files:
            if filename.endswith('.wav'):
            # Join the two strings in order to form the full filepath.
                filepath = os.path.join(root, filename)
                file_paths.append(filepath)  # Add it to the list.
                # pdb.set_trace()

    return file_paths  # Self-explanatory.