Home > In Python > Python Invalid Arguments Error

Python Invalid Arguments Error

Contents

It is a subclass of UnicodeError. TL;DR: Just use ValueError, but include a helpful message (e.g., raise ValueError("I'm afraid I can't let you do that, Dave. -HAL 9000"). New in version 1.5.2. It directly inherits from BaseException instead of Exception since it is technically not an error. this content

Can you move a levitating target 120 feet in a single action? Jokes about Monica's haircut Unix Exit Command Breaking effort on both Weak and Strong collision resistance hash values Nested apply function at a list How can I Improve gameplay for new A call to sys.exit() is translated into an exception so that clean-up handlers (finally clauses of try statements) can be executed, and so that a debugger can execute append_const Save a value defined in the argument specification to a list. http://stackoverflow.com/questions/256222/which-exception-should-i-raise-on-bad-illegal-argument-combinations-in-python

What Is The Argument Of An Exception In Python Quiz

The associated value is a string indicating what precisely went wrong. asked 4 years ago viewed 3022 times active 4 years ago Blog Stack Overflow Podcast #92 - The Guerilla Guide to Interviewing Get the weekly newsletter! Arguments containing -¶ The parse_args() method attempts to give errors whenever the user has clearly made a mistake, but some situations are inherently ambiguous. After that running 'print pyproj.pyproj_datadir' shold give correct location, and 'os.path.exists(pyproj.pyproj_datadir + '/epsg')' should return true.

This is useful for testing at the interactive prompt: >>> parser = argparse.ArgumentParser() >>> parser.add_argument( ... 'integers', metavar='int', type=int, choices=xrange(10), ... This can be achieved by passing False as the add_help= argument to ArgumentParser: >>> parser = argparse.ArgumentParser(prog='PROG', add_help=False) >>> parser.add_argument('--foo', help='foo help') >>> parser.print_help() usage: PROG [--foo FOO] vars). Python Exception Get Message If the associated value is a plain integer, it specifies the system exit status (passed to C's exit() function); if it is None, the exit status is zero; if

param = 10 ... >>> param 10 >>> function(param) In this example, to raise an exception is pow not function, so it's a good practice to separate the the two different In my case, I accept a key argument, but I want to restrict the set of characters in the key, such that only /\A[\w.]+\Z/ (Perl/Ruby regular expression) is accepted. import argparse parser = argparse.ArgumentParser(add_help=True) parser.add_argument('-a', action="store_true", default=False) parser.add_argument('-b', action="store", dest="b") parser.add_argument('-c', action="store", dest="c", type=int) print parser.parse_args() The help options (-h and --help) are added by default, but can be disabled http://stackoverflow.com/questions/9026675/invalid-argument-raise-exception exception ArithmeticError¶ The base class for those built-in exceptions that are raised for various arithmetic errors: OverflowError, ZeroDivisionError, FloatingPointError.

exception RecursionError¶ This exception is derived from RuntimeError. Invalid Argument Exception Java The following exceptions are kept for compatibility with previous versions; starting from Python 3.3, they are aliases of OSError. The tuple itself is also available on the args attribute. The type keyword argument of add_argument() allows any necessary type-checking and type conversions to be performed.

Python Valueerror Example

Raising exceptions When an error occurs in your program, you may either print a message and use sys.exit(1) to abort the program, or you may raise an exception. https://docs.python.org/2/library/exceptions.html The parser class is ArgumentParser. What Is The Argument Of An Exception In Python Quiz If a builtin exception fits, use it.. –dbr Nov 4 '08 at 8:29 3 As stated, the documentation is ambiguous. Python Raise Typeerror The built-in exceptions listed below can be generated by the interpreter or built-in functions.

To make an option required, True can be specified for the required= keyword argument to add_argument(): >>> parser = argparse.ArgumentParser() >>> parser.add_argument('--foo', required=True) >>> parser.parse_args(['--foo', 'BAR']) Namespace(foo='BAR') >>> http://caribtechsxm.com/in-python/python-print-to-error-out.php Comparing with optparse Setting up a Parser Defining Arguments Parsing a Command Line Simple Examples Argument Actions Option Prefixes Sources of Arguments Automatically Generated Options Parser Organization Sharing Parser Rules Conflicting help='the bar to %(prog)s (default: %(default)s)') >>> parser.print_help() usage: frobble [-h] [bar] positional arguments: bar the bar to frobble (default: 42) optional arguments: -h, --help show this help message and exit import argparse parser = argparse.ArgumentParser() parser.add_argument('-i', type=int) parser.add_argument('-f', type=float) parser.add_argument('--file', type=file) try: print parser.parse_args() except IOError, msg: parser.error(str(msg)) Any callable that takes a single string argument can be passed as type, Python Custom Exception

  1. This cannot occur for integers (which would rather raise MemoryError than give up).
  2. It is a subclass of UnicodeError.
  3. exception FutureWarning¶ Base class for warnings about constructs that will change semantically in the future.
  4. Generally, these calls tell the ArgumentParser how to take the strings on the command line and turn them into objects.
  5. for options like +f or /foo, may specify them using the prefix_chars= argument to the ArgumentParser constructor: >>> parser = argparse.ArgumentParser(prog='PROG', prefix_chars='-+') >>> parser.add_argument('+f') >>> parser.add_argument('++bar') >>> parser.parse_args('+f
  6. Be sure to report the version of the Python interpreter (sys.version; it is also printed at the start of an interactive Python session), the exact error message (the exception's associated

description='A foo that bars', ... When parsing the command line, if the option string is encountered with no command-line argument following it, the value of const will be assumed instead. Changed in version 3.3: EnvironmentError, IOError, WindowsError, socket.error, select.error and mmap.error have been merged into OSError, and the constructor may return a subclass. have a peek at these guys exception AttributeError¶ Raised when an attribute reference (see Attribute references) or assignment fails. (When an object does not support attribute references or attribute assignments at all, TypeError is raised.) exception

print '%r %r %r' % (namespace, values, option_string) ... Name Of Errors In Python Instances have an attribute code which is set to the proposed exit status or error message (defaulting to None). What does "they are facing their chest and shoulder" mean in this paragraph?

Classes are good.

Instances of this class have attributes filename, lineno, offset and text for easier access to the details. str() of the exception instance returns only the message. For example, err.object[err.start:err.end] gives the particular invalid input that the codec failed on. exception TabError¶ Raised when indentation contains an inconsistent use of tabs and spaces. Error Message Indicates In Python Instances of Action (or return value of any callable to the action parameter) should have attributes "dest", "option_strings", "default", "type", "required", "help", etc.

You should report this to the author or maintainer of your Python interpreter. It is a subclass of ValueError. UnicodeError has attributes that describe the encoding or decoding error. exception UnicodeDecodeError¶ Raised when a Unicode-related error occurs during decoding. check my blog exception NameError¶ Raised when a local or global name is not found.

For example: >>> parser = argparse.ArgumentParser() >>> parser.add_argument('--str', dest='types', action='append_const', const=str) >>> parser.add_argument('--int', dest='types', action='append_const', const=int) >>> parser.parse_args('--str --int'.split()) Namespace(types=[, ]) 'count' - This counts the number of Your simple quotes are part a the string –Benjamin Apr 14 at 8:28 add a comment| active oldest votes Know someone who can answer? help='foo the bars before frobbling') >>> parser.add_argument('bar', nargs='+', ... For positional, required, arguments, option_string is always None. $ python argparse_custom_action.py Initializing CustomAction dest = 'a' option_strings = ['-a'] required = False Initializing CustomAction dest = 'm' nargs = '*' option_strings

Otherwise, the ArgumentParser will see two -h/--help options (one in the parent and one in the child) and raise an error. exception ImportWarning¶ Base class for warnings about probable mistakes in module imports. New in version 2.5. New programs should probably use argparse, if it is available on all deployment platforms.

Corresponds to errno EEXIST. exception RuntimeError¶ Raised when an error is detected that doesn't fall in any of the other categories. P.