cannot open file in write mode, no such file or directory

[Steve Holden]

Kartic wrote:
>>I'm having a problem where when trying to open a file in write mode,
> 
> I
> 
>>get an IOError stating no such file or directory.  I'm calling an
>>external program which takes an input file and produces an output
> 
> file
> 
>>repeatedly, simulating the input file separately for each replicate.
>>The error occurs when trying to open the input file to write out the
>>new data.  The problem is difficult to reproduce since it only shows
> 
> up
> 
>>once every few thousand replicates.  I've tried using both os.system
> 
> 
> I am afraid you need to give more information that just IOError,
> calling an external program.
> 
> Please post the exact message including the input filename at the time
> the program went down. If you don't print the filename, please modify
> your program to do so.
> 
> A shot in the dark solution to your problem might be that you are
> dynamically  generating a filename and that filename probably contains
> characters not allowed by the local file system OR you generate a path
> that does not exist. For open() to work with the 'w' flag, the path
> where the file you say should be created should exist.
> 
Another low-probability cause is that you are trying to create files in 
a non-existent directory.

regards
  Steve