Python 如何检查文件是否已打开（在同一进程中）
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How to check if a file is already opened (in the same process)
提问by maximedupre
And I'd like to specifically achieve that with the try catch construct.
我想通过 try catch 构造专门实现这一点。
This related questionsuggests that I can do:
这个相关的问题表明我可以这样做：
try:
open(fileName, 'wb+')
except:
print("File already opened!")
raise
However, it doesn't work me. I can open the same file multiple times without any problem:
但是，它对我不起作用。我可以多次打开同一个文件，没有任何问题：
fileObj1 = open(fileName, 'wb+')
fileObj2 = open(fileName, 'wb+')
Is it because I have Python 3.5? Or because I'm using Raspbian?
是因为我有 Python 3.5 吗？还是因为我使用的是Raspbian？
Thanks for the help!
谢谢您的帮助！
采纳答案by atakanyenel
You open the same file but assign them to different variables. What you should do is:
您打开同一个文件，但将它们分配给不同的变量。你应该做的是：
fileobj=open(filename,"wb+")
if not fileobj.closed:
print("file is already opened")`
I'm writing with my phone so the styling may not be good but you will get the point. By the way the .closedonly checks if the file has been opened by the same python process.
我正在用我的手机写作，所以造型可能不太好，但你会明白的。顺便说一下，.closed唯一检查文件是否已被同一个 python 进程打开。
回答by TheLazyScripter
I would suggest using something like this
我建议使用这样的东西
# Only works on Windows
def is_open(file_name):
if os.path.exists(file_name):
try:
os.rename(file_name, file_name) #can't rename an open file so an error will be thrown
return False
except:
return True
raise NameError
Edited to fit the OP's specific issues
编辑以适应 OP 的特定问题
class FileObject(object):
def __init__(self, file_name):
self.file_name = file_name
self.__file = None
self.__locked = False
@property
def file(self):
return self.__file
@property
def locked(self):
return self.__locked
def open(self, mode, lock=True):#any testing on file should go before the if statement such as os.path.exists()
#replace mode with *args if you want to pass multiple modes
if not self.locked:
self.__locked = lock
self.__file = open(self.file_name, mode)
return self.file
else:
print 'Cannot open file because it has an exclusive lock placed on it'
return None #do whatever you want to do if the file is already open here
def close(self):
if self.file != None:
self.__file.close()
self.__file = None
self.__locked = False
def unlock(self):
if self.file != None:
self.__locked = False
