Python Catching Syntax Error
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Badges Ask Question x Dismiss Join the Stack Overflow Community Stack Overflow is a community of 6.2 million programmers, just like you, helping syntax for generic except clause in python each other. Join them; it only takes a minute: Sign up Failed to catch syntax error python up vote 8 down vote favorite 1 try: x===x except SyntaxError: print "You cannot do that" outputs x===x ^ SyntaxError: invalid syntax python raise custom exception this does not catch it either try: x===x except: print "You cannot do that" Other errors like NameError, ValueError, are catchable. Thoughts? System specs: import sys print(sys.version) -> 2.7.5 (default, Mar 9 2014, 22:15:05) [GCC 4.2.1 Compatible Apple LLVM 5.0 (clang-500.0.68)] python error-handling share|improve this question asked Jul 31 '14 at 1:18 humanbeing 404313 Syntax error is not a run-time error. You cannot catch it. –univerio Jul 31 '14 at 1:21 @univerio I
Python Print Exception
think you meant "runtime error". –zwol Jul 31 '14 at 1:21 @Zack Oops, corrected. Thanks! –univerio Jul 31 '14 at 1:22 add a comment| 2 Answers 2 active oldest votes up vote 13 down vote accepted You can only catch SyntaxError if it's thrown out of an eval or exec operation. >>> try: ... eval('x === x') ... except SyntaxError: ... print "You cannot do that" ... You cannot do that This is because, normally, the interpreter parses the entire file before executing any of it, so it detects the syntax error before the try statement is executed. If you use eval or its friends to cause more code to be parsed during the execution of the program, though, then you can catch it. I'm pretty sure this is in the official manual somewhere, but I can't find it right now. share|improve this answer answered Jul 31 '14 at 1:25 zwol 69k20116199 add a comment| up vote 8 down vote SyntaxErrors get raised when the file/code is parsed, not when that line of code is executed. The reason for this is simple -- If the syntax is wrong at a single point in the code, the parser can't continue so all code after that line is un-parseable. In other words, you can only catch syntax errors when python is trying to parse something. This includes exec, eva
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Name Of Errors In Python
of 6.2 million programmers, just like you, helping each other. Join them; it only takes a minute: Sign up What's wrong with my try: except: syntax? up vote 2 down vote favorite Choking code: while port http://stackoverflow.com/questions/25049498/failed-to-catch-syntax-error-python < 0 or port > 65535: try: port = int(raw_input("Enter port: ") except ValueError: print "Invalid port number." Result: File "/Users/.../Documents/.../CS 176A/TCPServer.py", line 10 except ValueError: ^ SyntaxError: invalid syntax python exception-handling syntax-error share|improve this question asked Sep 28 '10 at 6:40 Brian D 3,27293978 What tutorial are you using? What code editor are you using? –S.Lott Sep 28 '10 at 10:01 There was no tutorial. I http://stackoverflow.com/questions/3810279/whats-wrong-with-my-try-except-syntax was just trying to build a simple TCP server and client. TextWrangler is the editor. –Brian D Oct 9 '10 at 20:14 add a comment| 2 Answers 2 active oldest votes up vote 18 down vote accepted Missing right parenthesis. Change to port = int(raw_input("Enter port: ")) share|improve this answer answered Sep 28 '10 at 6:41 Manoj Govindan 35.1k1393101 Thanks. Not seeing clearly. –Brian D Sep 28 '10 at 6:42 by 9 seconds. that was down to the wire. –aaronasterling Sep 28 '10 at 6:42 1 @Aaron: =P #padding to post the comment. –Manoj Govindan Sep 28 '10 at 6:44 Haha yeah, you guys are both pretty fast.. good work. –Brian D Sep 28 '10 at 6:44 add a comment| up vote 11 down vote BTW, as a rule, whenever you receive interpreter/compiler errors, start looking for problems one line before the reported line. share|improve this answer answered Sep 28 '10 at 6:53 bgbg 7,9391668125 Yeah, that's a good tip. I was focused on the except, thinking it was my version of python or something not imported... thanks. –Brian D Sep 28 '10 at 6:56 add a comment| Your Answer draft saved draft discarded Sign up or log in Sign up using Googl
Pages Local Site Map ------------------------ Rename Page Delete Page ------------------------ ------------------------ Remove Spam Revert to this revision ------------------------ SlideShow User Login Handling Exceptions The simplest way to handle exceptions is with a "try-except" block: 1 (x,y) = (5,0) 2 try: 3 z = x/y 4 except ZeroDivisionError: 5 print "divide by zero" If you wanted to examine the exception https://wiki.python.org/moin/HandlingExceptions from code, you could have: 1 (x,y) = (5,0) 2 try: 3 z = x/y 4 except ZeroDivisionError as e: 5 z = e # representation: " Error: %s