What is a good way to handle exceptions when trying to read a file in python

Question

I want to read a  csv file in python   I don t know if the file exists  My current solution is below  It feels sloppy to me because the two separate exception tests are awkwardly juxtaposed   Is there a prettier way to do it  import csv     fName    quot aFile csv quot   try      with open fName   rb   as f          reader   csv reader f          for row in reader              pass  do stuff here      except IOError      print  quot Could not read file  quot   fName

User · Accepted Answer

How about this   try      f   open fname   rb   except OSError      print  Could not open read file    fname     sys exit    with f      reader   csv reader f      for row in reader          pass  do stuff here

User · Answer

Adding to  Josh s example   fName    FILE TO OPEN  if os path exists fName       with open fName   rb   as f           add you code to handle the file contents here  elif IOError      print  Unable to open file    str fName    This way you can attempt to open the file  but if it doesn t exist  if it raises an IOError   alert the user

User · Answer

I guess I misunderstood what was being asked  Re-re-reading  it looks like Tim s answer is what you want  Let me just add this  however  if you want to catch an exception from open  then open has to be wrapped in a try  If the call to open is in the header of a with  then the with has to be in a try to catch the exception  There s no way around that   So the answer is either   Tim s way  or  No  you re doing it correctly       Previous unhelpful answer to which all the comments refer   import os  if os path exists fName      with open fName   rb   as f         try               do stuff        except     whatever reader errors you care about              handle error

User · Answer

fname    filenotfound txt  try      f   open fname   rb   except FileNotFoundError      print  quot file    does not exist quot  format fname    file filenotfound txt does not exist  exception FileNotFoundError Raised when a file or directory is requested but doesn   t exist  Corresponds to errno ENOENT  https   docs python org 3 library exceptions html This exception does not exist in Python 2

User · Answer

Here is a read write example   The with statements insure the close   statement will be called by the file object regardless of whether an exception is thrown   http   effbot org zone python-with-statement htm  import sys  fIn    symbolsIn csv  fOut    symbolsOut csv   try     with open fIn   r   as f        file content   f read         print  read file     fIn    if not file content        print  no data in file     fIn       file content    name phone address n     with open fOut   w   as dest        dest write file content        print  wrote file     fOut except IOError as e     print  I O error  0     1   format e errno  e strerror  except   handle other exceptions such as attribute errors    print  Unexpected error    sys exc info   0  print  done

[python] What is a good way to handle exceptions when trying to read a file in python?

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