Python File Io Error Handling
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Python Exception Message
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Syntax For Generic Except Clause In Python
when trying to read a file in python? up vote 9 down vote favorite 2 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 prettier way to do it? import csv fName = "aFile.csv" try: with open(fName, 'rb') as f:
Is Nested Try Block Possible In Python
reader = csv.reader(f) for row in reader: pass #do stuff here except IOError: print "Could not read file:", fName python file-io exception-handling share|improve this question edited Apr 11 '11 at 21:08 asked Apr 11 '11 at 20:51 CharlesHolbrow 1,05431621 add a comment| 4 Answers 4 active oldest votes up vote 6 down vote accepted 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 share|improve this answer edited Apr 11 '11 at 21:23 answered Apr 11 '11 at 20:55 Josh Caswell 52.6k11103152 5 Just because a file exists do
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Name Of Errors In Python
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exceptions While a program is running, its data is in memory. When the program ends, or the computer shuts down, data in memory disappears. To store data permanently, http://www.greenteapress.com/thinkpython/thinkCSpy/html/chap11.html you have to put it in a file. Files are usually stored on a hard drive, floppy drive, or CD-ROM. When there are a large number of files, they are often organized http://crashcourse.housegordon.org/python-exceptions-handling-tips.html into directories (also called "folders"). Each file is identified by a unique name, or a combination of a file name and a directory name. By reading and writing files, programs can in python exchange information with each other and generate printable formats like PDF. Working with files is a lot like working with books. To use a book, you have to open it. When you're done, you have to close it. While the book is open, you can either write in it or read from it. In either case, you know where you are in the book. python file io Most of the time, you read the whole book in its natural order, but you can also skip around. All of this applies to files as well. To open a file, you specify its name and indicate whether you want to read or write. Opening a file creates a file object. In this example, the variable f refers to the new file object. >>> f = open("test.dat","w") >>> print f
generic Exception. Use user-defined exceptions for application-level errors. Update, 2016-02-26 The kind folks at Webucator made a video based on this post. Check out the video at: https://youtu.be/T94vZmOZodY and other Webucator Online Python Classes. Disclaimer: I’m not a python fan (and certainly not an expert). Comments, feedback, suggestions and improvements are welcomed. without catching exceptions This typical python code: #!/usr/bin/env python import sys a = open("/non/existing/file","r") Will result in this output: $ ./bad0.py Traceback (most recent call last): File "./bad0.py", line 3, in