> For the complete documentation index, see [llms.txt](https://l1nwatch.gitbook.io/interview_exercise/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://l1nwatch.gitbook.io/interview_exercise/stackoverflow-about-python/jian-cha-wen-jian-jia-shi-fou-cun-zai-de-cao-zuo.md).

# 检查文件夹是否存在的操作

方法一：

```python
filename = "/my/directory/filename.txt"
dir = os.path.dirname(filename)

try:
    os.stat(dir)
except:
    os.mkdir(dir)

f = file(filename)
```

方法二：

```python
def ensure_dir(f):
    d = os.path.dirname(f)
    if not os.path.exists(d):
        os.makedirs(d)
```

【注意】，如果在调用 `os.path.exists` 和 `os.makedirs` 之间被创建了，将会出现一个 `OSError`。然而捕获 `OSError` 并不能很好地解决这个问题，因为它将会忽略磁盘空间不足，没有足够权限等一些其他造成文件创建失败的因素

一个做法是捕获 OSError 异常并检查返回的错误代码

方法三：

```python
os.makedirs(self.path_dir, exist_ok=True)
```


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