Python Open File Catch Error
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Is Nested Try Block Possible In Python
How “with” is better than try/catch to open a file in Python? up vote 16 down vote favorite 1 I got that the with statement help you to turn this: try: f = open(my_file) do_stuff_that_fails() except: pass finally: f.close() Into: with open(my_file) as f: do_stuff_that_fails() But how is that better? You still got to handle the case with the file not being able name of errors in python to be opened (like prompting the user to tell him he doesn't have permissions), so in reality you'd have: try: with open(my_file) as f: do_stuff_that_fails() except (IOError, OSError, Failure) as e: do_stuff_when_it_doesnt_work() Which is equivalent to: try: f = open(my_file) do_stuff_that_fails() except (IOError, OSError, Faillure) as e: do_stuff_when_it_doesnt_work() finally: f.close() Yes, you gained two lines, but you added a level of nesting wich doesn't make it easier to read. Is the purpose of the with statement to save you two lines or am I missing something? It seems a lot to add a keyword just for that, so I feel like there is some syntaxe to handle the additional try/except that I don't know about. python exception with-statement share|improve this question edited Jan 8 '12 at 11:45 skaffman 278k63619658 asked Jan 8 '12 at 2:05 e-satis 252k83236287 2 "with" is going to be an awful tag name, subject to newbie abuse. Can we find something better? –Charles Jan 8 '12 at 4:26 +1 What about with-keyword ? –e-satis Jan 8 '12 at 8:22 Python needs a: trywith open('whatever', 'r') as f: .
you have probably seen some. There are (at least) two distinguishable kinds of errors: syntax errors and exceptions. 8.1. Syntax Errors¶ Syntax errors, also known syntax for raise clause in python as parsing errors, are perhaps the most common kind of complaint you
An Exception Can Be In Python
get while you are still learning Python: >>> while True print 'Hello world' File "
Python Try Else
print 'Hello world' ^ SyntaxError: invalid syntax The parser repeats the offending line and displays a little ‘arrow' pointing at the earliest point in the line where the error was detected. http://stackoverflow.com/questions/8774830/how-with-is-better-than-try-catch-to-open-a-file-in-python The error is caused by (or at least detected at) the token preceding the arrow: in the example, the error is detected at the keyword print, since a colon (':') is missing before it. File name and line number are printed so you know where to look in case the input came from a script. 8.2. Exceptions¶ Even if a https://docs.python.org/2.7/tutorial/errors.html statement or expression is syntactically correct, it may cause an error when an attempt is made to execute it. Errors detected during execution are called exceptions and are not unconditionally fatal: you will soon learn how to handle them in Python programs. Most exceptions are not handled by programs, however, and result in error messages as shown here: >>> 10 * (1/0) Traceback (most recent call last): File "
you have probably seen some. There are (at least) two distinguishable kinds of errors: syntax errors and exceptions. https://docs.python.org/3/tutorial/errors.html 8.1. Syntax Errors¶ Syntax errors, also known as parsing errors, are perhaps the most common kind of complaint you get while you are still learning Python: >>> while http://www.python-course.eu/exception_handling.php True print('Hello world') File "
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