Python Io Error
Contents |
This module never needs to be imported explicitly: the exceptions are provided in the built-in namespace as well as the exceptions module. For class exceptions, in a try statement with python exception message an except clause that mentions a particular class, that clause also handles python custom exception any exception classes derived from that class (but not exception classes from which it is derived). Two exception classes that
Python Raise Valueerror
are not related via subclassing are never equivalent, even if they have the same name. The built-in exceptions listed below can be generated by the interpreter or built-in functions. Except where mentioned, they
Python Filenotfounderror
have an "associated value" indicating the detailed cause of the error. This may be a string or a tuple containing several items of information (e.g., an error code and a string explaining the code). The associated value is the second argument to the raise statement. If the exception class is derived from the standard root class BaseException, the associated value is present as the exception python errno instance's args attribute. User code can raise built-in exceptions. This can be used to test an exception handler or to report an error condition "just like" the situation in which the interpreter raises the same exception; but beware that there is nothing to prevent user code from raising an inappropriate error. The built-in exception classes can be subclassed to define new exceptions; programmers are encouraged to derive new exceptions from the Exception class or one of its subclasses, and not from BaseException. More information on defining exceptions is available in the Python Tutorial under User-defined Exceptions. The following exceptions are only used as base classes for other exceptions. exception BaseException¶ The base class for all built-in exceptions. It is not meant to be directly inherited by user-defined classes (for that, use Exception). If str() or unicode() is called on an instance of this class, the representation of the argument(s) to the instance are returned, or the empty string when there were no arguments. New in version 2.5. args¶ The tuple of arguments given to the exception constructor. Some built-in exceptions (like IOError) expect a certain number of arguments and assign
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
Python Exception Class Methods
known as parsing errors, are perhaps the most common kind of complaint python attributeerror object has no attribute you get while you are still learning Python: >>> while True print 'Hello world' File "
This module makes available standard errno system symbols. The value of each symbol is the corresponding integer value. The names and descriptions are borrowed from linux/include/errno.h, which https://docs.python.org/2/library/errno.html should be pretty all-inclusive. errno.errorcode¶ Dictionary providing a mapping from the errno value to the string name in the underlying system. For instance, errno.errorcode[errno.EPERM] maps to 'EPERM'. To http://stackoverflow.com/questions/29347790/difference-between-ioerror-and-oserror translate a numeric error code to an error message, use os.strerror(). Of the following list, symbols that are not used on the current platform are not defined by the python exception module. The specific list of defined symbols is available as errno.errorcode.keys(). Symbols available can include: errno.EPERM¶ Operation not permitted errno.ENOENT¶ No such file or directory errno.ESRCH¶ No such process errno.EINTR¶ Interrupted system call errno.EIO¶ I/O error errno.ENXIO¶ No such device or address errno.E2BIG¶ Arg list too long errno.ENOEXEC¶ Exec format error errno.EBADF¶ Bad file number errno.ECHILD¶ No child processes python io error errno.EAGAIN¶ Try again errno.ENOMEM¶ Out of memory errno.EACCES¶ Permission denied errno.EFAULT¶ Bad address errno.ENOTBLK¶ Block device required errno.EBUSY¶ Device or resource busy errno.EEXIST¶ File exists errno.EXDEV¶ Cross-device link errno.ENODEV¶ No such device errno.ENOTDIR¶ Not a directory errno.EISDIR¶ Is a directory errno.EINVAL¶ Invalid argument errno.ENFILE¶ File table overflow errno.EMFILE¶ Too many open files errno.ENOTTY¶ Not a typewriter errno.ETXTBSY¶ Text file busy errno.EFBIG¶ File too large errno.ENOSPC¶ No space left on device errno.ESPIPE¶ Illegal seek errno.EROFS¶ Read-only file system errno.EMLINK¶ Too many links errno.EPIPE¶ Broken pipe errno.EDOM¶ Math argument out of domain of func errno.ERANGE¶ Math result not representable errno.EDEADLK¶ Resource deadlock would occur errno.ENAMETOOLONG¶ File name too long errno.ENOLCK¶ No record locks available errno.ENOSYS¶ Function not implemented errno.ENOTEMPTY¶ Directory not empty errno.ELOOP¶ Too many symbolic links encountered errno.EWOULDBLOCK¶ Operation would block errno.ENOMSG¶ No message of desired type errno.EIDRM¶ Identifier removed errno.ECHRNG¶ Channel number out of range errno.EL2NSYNC¶ Level 2 not synchronized errno.EL3HLT¶ Level 3 halted errno.EL3RST¶ Level 3 reset errno.ELNRNG¶ Link number out of range errno.EUNATCH¶ Protocol driver not attached errno.ENOCSI¶ No CSI structure available errno.EL2HLT¶ Level 2 halted errno.EBADE
here for a quick overview of the site Help Center Detailed answers to any questions you might have Meta Discuss the workings and policies of this site About Us Learn more about Stack Overflow the company Business Learn more about hiring developers or posting ads with us Stack Overflow Questions Jobs Documentation Tags Users Badges Ask Question x Dismiss Join the Stack Overflow Community Stack Overflow is a community of 6.2 million programmers, just like you, helping each other. Join them; it only takes a minute: Sign up Difference between IOError and OSError? up vote 5 down vote favorite 1 I am always getting confused on whether a function would raise an IOError or OSError (or both?). What is the principle rule behind these exception types, what is the difference between them and when is which raised? I've initially thought OSError is for things like permission denial, but opening a file without permissions will raise an IOError. python exception python-2.x share|improve this question edited Mar 30 '15 at 13:44 asked Mar 30 '15 at 13:42 Niklas R 4,6771042105 4 Changed in version 3.3: EnvironmentError, IOError, WindowsError, VMSError, socket.error, select.error and mmap.error have been merged into OSError. E.g. just throw OSError and forget about IOError. –Martijn Pieters♦ Mar 30 '15 at 13:44 @MartijnPieters Thanks, I've added the Python 2 tag. Just throwing OSError sounds good to me, yet I'm always having trouble to know when a function like shutil.copyfile() or os.access() would raise IOError or OSError (always have to look it up) –Niklas R Mar 30 '15 at 13:44 2 Also see python.org/dev/peps/pep-3151 for the background on this, it'll help put the two exceptions into perspective. –Martijn Pieters♦ Mar 30 '15 at 13:44 1 If you are getting confused by it - well, that's one reason to switch to Python 3 then. –Antti Haapala Mar 30 '15 at 13:46 2 @AnttiHaapala I do use Python 3 for standalone projects, but its a different story in an embedded Python environment. :) –Niklas R Mar 30 '1