{ "metadata": { "name": "Python basics, loose ends" }, "nbformat": 2, "worksheets": [ { "cells": [ { "cell_type": "code", "collapsed": false, "input": [ "# patching objects and classes", "class Point(object):", " def __init__(self, x, y):", " self.x=x", " self.y=y", " ", "x1, x2 = Point(1,1), Point(2,3)", "x1.distance(x2)" ], "language": "python", "outputs": [ { "ename": "AttributeError", "evalue": "'Point' object has no attribute 'distance'", "output_type": "pyerr", "traceback": [ "\u001b[1;31m---------------------------------------------------------------------------\u001b[0m\n\u001b[1;31mAttributeError\u001b[0m Traceback (most recent call last)", "\u001b[1;32m/home/stef/tasks/pywik/\u001b[0m in \u001b[0;36m\u001b[1;34m()\u001b[0m\n\u001b[0;32m 6\u001b[0m \u001b[1;33m\u001b[0m\u001b[0m\n\u001b[0;32m 7\u001b[0m \u001b[0mx1\u001b[0m\u001b[1;33m,\u001b[0m \u001b[0mx2\u001b[0m \u001b[1;33m=\u001b[0m \u001b[0mPoint\u001b[0m\u001b[1;33m(\u001b[0m\u001b[1;36m1\u001b[0m\u001b[1;33m,\u001b[0m\u001b[1;36m1\u001b[0m\u001b[1;33m)\u001b[0m\u001b[1;33m,\u001b[0m \u001b[0mPoint\u001b[0m\u001b[1;33m(\u001b[0m\u001b[1;36m2\u001b[0m\u001b[1;33m,\u001b[0m\u001b[1;36m3\u001b[0m\u001b[1;33m)\u001b[0m\u001b[1;33m\u001b[0m\u001b[0m\n\u001b[1;32m----> 8\u001b[1;33m \u001b[0mx1\u001b[0m\u001b[1;33m.\u001b[0m\u001b[0mdistance\u001b[0m\u001b[1;33m(\u001b[0m\u001b[0mx2\u001b[0m\u001b[1;33m)\u001b[0m\u001b[1;33m\u001b[0m\u001b[0m\n\u001b[0m", "\u001b[1;31mAttributeError\u001b[0m: 'Point' object has no attribute 'distance'" ] } ], "prompt_number": 57 }, { "cell_type": "code", "collapsed": false, "input": [ "def distance(self,other):", " return sqrt((self.x-other.x)**2 + (self.y-other.y)**2)", "x1.distance=distance", "x1.distance(x2)", "x2.distance(x1)" ], "language": "python", "outputs": [ { "ename": "TypeError", "evalue": "distance() takes exactly 2 arguments (1 given)", "output_type": "pyerr", "traceback": [ "\u001b[1;31m---------------------------------------------------------------------------\u001b[0m\n\u001b[1;31mTypeError\u001b[0m Traceback (most recent call last)", "\u001b[1;32m/home/stef/tasks/pywik/\u001b[0m in \u001b[0;36m\u001b[1;34m()\u001b[0m\n\u001b[0;32m 2\u001b[0m \u001b[1;32mreturn\u001b[0m \u001b[0msqrt\u001b[0m\u001b[1;33m(\u001b[0m\u001b[1;33m(\u001b[0m\u001b[0mself\u001b[0m\u001b[1;33m.\u001b[0m\u001b[0mx\u001b[0m\u001b[1;33m-\u001b[0m\u001b[0mother\u001b[0m\u001b[1;33m.\u001b[0m\u001b[0mx\u001b[0m\u001b[1;33m)\u001b[0m\u001b[1;33m**\u001b[0m\u001b[1;36m2\u001b[0m \u001b[1;33m+\u001b[0m \u001b[1;33m(\u001b[0m\u001b[0mself\u001b[0m\u001b[1;33m.\u001b[0m\u001b[0my\u001b[0m\u001b[1;33m-\u001b[0m\u001b[0mother\u001b[0m\u001b[1;33m.\u001b[0m\u001b[0my\u001b[0m\u001b[1;33m)\u001b[0m\u001b[1;33m**\u001b[0m\u001b[1;36m2\u001b[0m\u001b[1;33m)\u001b[0m\u001b[1;33m\u001b[0m\u001b[0m\n\u001b[0;32m 3\u001b[0m \u001b[0mx1\u001b[0m\u001b[1;33m.\u001b[0m\u001b[0mdistance\u001b[0m\u001b[1;33m=\u001b[0m\u001b[0mdistance\u001b[0m\u001b[1;33m\u001b[0m\u001b[0m\n\u001b[1;32m----> 4\u001b[1;33m \u001b[0mx1\u001b[0m\u001b[1;33m.\u001b[0m\u001b[0mdistance\u001b[0m\u001b[1;33m(\u001b[0m\u001b[0mx2\u001b[0m\u001b[1;33m)\u001b[0m\u001b[1;33m\u001b[0m\u001b[0m\n\u001b[0m\u001b[0;32m 5\u001b[0m \u001b[0mx2\u001b[0m\u001b[1;33m.\u001b[0m\u001b[0mdistance\u001b[0m\u001b[1;33m(\u001b[0m\u001b[0mx1\u001b[0m\u001b[1;33m)\u001b[0m\u001b[1;33m\u001b[0m\u001b[0m\n", "\u001b[1;31mTypeError\u001b[0m: distance() takes exactly 2 arguments (1 given)" ] } ], "prompt_number": 58 }, { "cell_type": "code", "collapsed": false, "input": [ "import types", "x1.distance=types.MethodType(distance,x1)", "print x1.distance(x2)", "x2.distance(x1)" ], "language": "python", "outputs": [ { "ename": "AttributeError", "evalue": "'Point' object has no attribute 'distance'", "output_type": "pyerr", "traceback": [ "\u001b[1;31m---------------------------------------------------------------------------\u001b[0m\n\u001b[1;31mAttributeError\u001b[0m Traceback (most recent call last)", "\u001b[1;32m/home/stef/tasks/pywik/\u001b[0m in \u001b[0;36m\u001b[1;34m()\u001b[0m\n\u001b[0;32m 2\u001b[0m \u001b[0mx1\u001b[0m\u001b[1;33m.\u001b[0m\u001b[0mdistance\u001b[0m\u001b[1;33m=\u001b[0m\u001b[0mtypes\u001b[0m\u001b[1;33m.\u001b[0m\u001b[0mMethodType\u001b[0m\u001b[1;33m(\u001b[0m\u001b[0mdistance\u001b[0m\u001b[1;33m,\u001b[0m\u001b[0mx1\u001b[0m\u001b[1;33m)\u001b[0m\u001b[1;33m\u001b[0m\u001b[0m\n\u001b[0;32m 3\u001b[0m \u001b[1;32mprint\u001b[0m \u001b[0mx1\u001b[0m\u001b[1;33m.\u001b[0m\u001b[0mdistance\u001b[0m\u001b[1;33m(\u001b[0m\u001b[0mx2\u001b[0m\u001b[1;33m)\u001b[0m\u001b[1;33m\u001b[0m\u001b[0m\n\u001b[1;32m----> 4\u001b[1;33m \u001b[0mx2\u001b[0m\u001b[1;33m.\u001b[0m\u001b[0mdistance\u001b[0m\u001b[1;33m(\u001b[0m\u001b[0mx1\u001b[0m\u001b[1;33m)\u001b[0m\u001b[1;33m\u001b[0m\u001b[0m\n\u001b[0m", "\u001b[1;31mAttributeError\u001b[0m: 'Point' object has no attribute 'distance'" ] }, { "output_type": "stream", "stream": "stdout", "text": [ "2.2360679775" ] } ], "prompt_number": 59 }, { "cell_type": "code", "collapsed": false, "input": [ "Point.distance=distance", "x2.distance(x1)" ], "language": "python", "outputs": [ { "output_type": "pyout", "prompt_number": 60, "text": [ "2.2360679774997898" ] } ], "prompt_number": 60 }, { "cell_type": "code", "collapsed": false, "input": [ "# decorators http://wiki.python.org/moin/PythonDecorators", "# http://stackoverflow.com/questions/739654/understanding-python-decorators", "def hello(name=\"World\"):", " return \"Hello %s!\" % name", "print hello()" ], "language": "python", "outputs": [ { "output_type": "stream", "stream": "stdout", "text": [ "Hello World!" ] } ], "prompt_number": 61 }, { "cell_type": "code", "collapsed": false, "input": [ "import hashlib", "print '0'", "def hashed(func):", " print \"hashed1\"", " def wrapped():", " print \"wrapped1\"", " res=func()", " return (res,hashlib.md5(res).hexdigest())", " print \"hashed2\"", " return wrapped", "print '1'", "@hashed", "def hashedhello(name=\"World\"):", " print \"hhello1\"", " return \"Hello %s!\" % name", "print '2'", "print hashedhello()" ], "language": "python", "outputs": [ { "output_type": "stream", "stream": "stdout", "text": [ "0", "1", "hashed1", "hashed2", "2", "wrapped1", "hhello1", "('Hello World!', 'ed076287532e86365e841e92bfc50d8c')" ] } ], "prompt_number": 63 }, { "cell_type": "code", "collapsed": false, "input": [ "import hmac", "def authd(key):", " def decor(func):", " def wrapped():", " res=func()", " return (res,hmac.new(key,res).hexdigest())", " return wrapped", " return decor", "", "@authd(\"secret\")", "def authdhello(name=\"World\"):", " return \"Hello %s!\" % name", "", "print authdhello()" ], "language": "python", "outputs": [ { "output_type": "stream", "stream": "stdout", "text": [ "('Hello World!', '09185d5e4c0a674aa431cb8411e327ad')" ] } ], "prompt_number": 64 }, { "cell_type": "code", "collapsed": false, "input": [ "def autokey(key):", " def decor(func):", " def wrapped(*args,**kwargs):", " res=func(*args,**kwargs)", " return ''.join([chr(ord(k)+ord(p))for k,p in zip(key+res,res)])", " return wrapped", " return decor", "", "@autokey(\"secret\")", "def secrethello(name=\"World\"):", " return \"Hello %s!\" % name", "", "msg=secrethello(name=\"python\")", "print repr(msg)" ], "language": "python", "outputs": [ { "output_type": "stream", "stream": "stdout", "text": [ "'\\xbb\\xca\\xcf\\xde\\xd4\\x94\\xb8\\xde\\xe0\\xd4\\xde\\x8e\\x91'" ] } ], "prompt_number": 65 }, { "cell_type": "code", "collapsed": false, "input": [ "def dekey(key, ct):", " res=key[:]", " for i, c in enumerate(ct):", " res=\"%s%s\" % (res,chr(ord(c)-ord(res[i])))", " return res[len(key):]", "", "print dekey('secret', secrethello(\"python\"))" ], "language": "python", "outputs": [ { "output_type": "stream", "stream": "stdout", "text": [ "Hello python!" ] } ], "prompt_number": 66 }, { "cell_type": "code", "collapsed": false, "input": [ "# see modules demos in hackerspace/python101", "dir(sys)" ], "language": "python", "outputs": [ { "output_type": "pyout", "prompt_number": 67, "text": [ "['__displayhook__',", " '__doc__',", " '__egginsert',", " '__excepthook__',", " '__name__',", " '__package__',", " '__plen',", " '__stderr__',", " '__stdin__',", " '__stdout__',", " '_clear_type_cache',", " '_current_frames',", " '_getframe',", " '_mercurial',", " 'api_version',", " 'argv',", " 'builtin_module_names',", " 'byteorder',", " 'call_tracing',", " 'callstats',", " 'copyright',", " 'displayhook',", " 'dont_write_bytecode',", " 'exc_clear',", " 'exc_info',", " 'exc_type',", " 'excepthook',", " 'exec_prefix',", " 'executable',", " 'exit',", " 'exitfunc',", " 'flags',", " 'float_info',", " 'float_repr_style',", " 'getcheckinterval',", " 'getdefaultencoding',", " 'getdlopenflags',", " 'getfilesystemencoding',", " 'getprofile',", " 'getrecursionlimit',", " 'getrefcount',", " 'getsizeof',", " 'gettrace',", " 'hexversion',", " 'last_traceback',", " 'last_type',", " 'last_value',", " 'long_info',", " 'maxint',", " 'maxsize',", " 'maxunicode',", " 'meta_path',", " 'modules',", " 'path',", " 'path_hooks',", " 'path_importer_cache',", " 'platform',", " 'prefix',", " 'py3kwarning',", " 'pydebug',", " 'real_prefix',", " 'setcheckinterval',", " 'setdlopenflags',", " 'setprofile',", " 'setrecursionlimit',", " 'settrace',", " 'stderr',", " 'stdin',", " 'stdout',", " 'subversion',", " 'version',", " 'version_info',", " 'warnoptions']" ] } ], "prompt_number": 67 }, { "cell_type": "code", "collapsed": false, "input": [ "help(sys)" ], "language": "python", "outputs": [ { "output_type": "stream", "stream": "stdout", "text": [ "Help on built-in module sys:", "", "NAME", " sys", "", "FILE", " (built-in)", "", "MODULE DOCS", " http://docs.python.org/library/sys", "", "DESCRIPTION", " This module provides access to some objects used or maintained by the", " interpreter and to functions that interact strongly with the interpreter.", " ", " Dynamic objects:", " ", " argv -- command line arguments; argv[0] is the script pathname if known", " path -- module search path; path[0] is the script directory, else ''", " modules -- dictionary of loaded modules", " ", " displayhook -- called to show results in an interactive session", " excepthook -- called to handle any uncaught exception other than SystemExit", " To customize printing in an interactive session or to install a custom", " top-level exception handler, assign other functions to replace these.", " ", " exitfunc -- if sys.exitfunc exists, this routine is called when Python exits", " Assigning to sys.exitfunc is deprecated; use the atexit module instead.", " ", " stdin -- standard input file object; used by raw_input() and input()", " stdout -- standard output file object; used by the print statement", " stderr -- standard error object; used for error messages", " By assigning other file objects (or objects that behave like files)", " to these, it is possible to redirect all of the interpreter's I/O.", " ", " last_type -- type of last uncaught exception", " last_value -- value of last uncaught exception", " last_traceback -- traceback of last uncaught exception", " These three are only available in an interactive session after a", " traceback has been printed.", " ", " exc_type -- type of exception currently being handled", " exc_value -- value of exception currently being handled", " exc_traceback -- traceback of exception currently being handled", " The function exc_info() should be used instead of these three,", " because it is thread-safe.", " ", " Static objects:", " ", " float_info -- a dict with information about the float inplementation.", " long_info -- a struct sequence with information about the long implementation.", " maxint -- the largest supported integer (the smallest is -maxint-1)", " maxsize -- the largest supported length of containers.", " maxunicode -- the largest supported character", " builtin_module_names -- tuple of module names built into this interpreter", " version -- the version of this interpreter as a string", " version_info -- version information as a named tuple", " hexversion -- version information encoded as a single integer", " copyright -- copyright notice pertaining to this interpreter", " platform -- platform identifier", " executable -- absolute path of the executable binary of the Python interpreter", " prefix -- prefix used to find the Python library", " exec_prefix -- prefix used to find the machine-specific Python library", " float_repr_style -- string indicating the style of repr() output for floats", " __stdin__ -- the original stdin; don't touch!", " __stdout__ -- the original stdout; don't touch!", " __stderr__ -- the original stderr; don't touch!", " __displayhook__ -- the original displayhook; don't touch!", " __excepthook__ -- the original excepthook; don't touch!", " ", " Functions:", " ", " displayhook() -- print an object to the screen, and save it in __builtin__._", " excepthook() -- print an exception and its traceback to sys.stderr", " exc_info() -- return thread-safe information about the current exception", " exc_clear() -- clear the exception state for the current thread", " exit() -- exit the interpreter by raising SystemExit", " getdlopenflags() -- returns flags to be used for dlopen() calls", " getprofile() -- get the global profiling function", " getrefcount() -- return the reference count for an object (plus one :-)", " getrecursionlimit() -- return the max recursion depth for the interpreter", " getsizeof() -- return the size of an object in bytes", " gettrace() -- get the global debug tracing function", " setcheckinterval() -- control how often the interpreter checks for events", " setdlopenflags() -- set the flags to be used for dlopen() calls", " setprofile() -- set the global profiling function", " setrecursionlimit() -- set the max recursion depth for the interpreter", " settrace() -- set the global debug tracing function", "", "FUNCTIONS", " __displayhook__ = displayhook(...)", " displayhook(object) -> None", " ", " Print an object to sys.stdout and also save it in __builtin__._", " ", " __excepthook__ = excepthook(...)", " excepthook(exctype, value, traceback) -> None", " ", " Handle an exception by displaying it with a traceback on sys.stderr.", " ", " call_tracing(...)", " call_tracing(func, args) -> object", " ", " Call func(*args), while tracing is enabled. The tracing state is", " saved, and restored afterwards. This is intended to be called from", " a debugger from a checkpoint, to recursively debug some other code.", " ", " callstats(...)", " callstats() -> tuple of integers", " ", " Return a tuple of function call statistics, if CALL_PROFILE was defined", " when Python was built. Otherwise, return None.", " ", " When enabled, this function returns detailed, implementation-specific", " details about the number of function calls executed. The return value is", " a 11-tuple where the entries in the tuple are counts of:", " 0. all function calls", " 1. calls to PyFunction_Type objects", " 2. PyFunction calls that do not create an argument tuple", " 3. PyFunction calls that do not create an argument tuple", " and bypass PyEval_EvalCodeEx()", " 4. PyMethod calls", " 5. PyMethod calls on bound methods", " 6. PyType calls", " 7. PyCFunction calls", " 8. generator calls", " 9. All other calls", " 10. Number of stack pops performed by call_function()", " ", " exc_clear(...)", " exc_clear() -> None", " ", " Clear global information on the current exception. Subsequent calls to", " exc_info() will return (None,None,None) until another exception is raised", " in the current thread or the execution stack returns to a frame where", " another exception is being handled.", " ", " exc_info(...)", " exc_info() -> (type, value, traceback)", " ", " Return information about the most recent exception caught by an except", " clause in the current stack frame or in an older stack frame.", " ", " exit(...)", " exit([status])", " ", " Exit the interpreter by raising SystemExit(status).", " If the status is omitted or None, it defaults to zero (i.e., success).", " If the status is numeric, it will be used as the system exit status.", " If it is another kind of object, it will be printed and the system", " exit status will be one (i.e., failure).", " ", " getcheckinterval(...)", " getcheckinterval() -> current check interval; see setcheckinterval().", " ", " getdefaultencoding(...)", " getdefaultencoding() -> string", " ", " Return the current default string encoding used by the Unicode ", " implementation.", " ", " getdlopenflags(...)", " getdlopenflags() -> int", " ", " Return the current value of the flags that are used for dlopen calls.", " The flag constants are defined in the ctypes and DLFCN modules.", " ", " getfilesystemencoding(...)", " getfilesystemencoding() -> string", " ", " Return the encoding used to convert Unicode filenames in", " operating system filenames.", " ", " getprofile(...)", " getprofile()", " ", " Return the profiling function set with sys.setprofile.", " See the profiler chapter in the library manual.", " ", " getrecursionlimit(...)", " getrecursionlimit()", " ", " Return the current value of the recursion limit, the maximum depth", " of the Python interpreter stack. This limit prevents infinite", " recursion from causing an overflow of the C stack and crashing Python.", " ", " getrefcount(...)", " getrefcount(object) -> integer", " ", " Return the reference count of object. The count returned is generally", " one higher than you might expect, because it includes the (temporary)", " reference as an argument to getrefcount().", " ", " getsizeof(...)", " getsizeof(object, default) -> int", " ", " Return the size of object in bytes.", " ", " gettrace(...)", " gettrace()", " ", " Return the global debug tracing function set with sys.settrace.", " See the debugger chapter in the library manual.", " ", " setcheckinterval(...)", " setcheckinterval(n)", " ", " Tell the Python interpreter to check for asynchronous events every", " n instructions. This also affects how often thread switches occur.", " ", " setdlopenflags(...)", " setdlopenflags(n) -> None", " ", " Set the flags used by the interpreter for dlopen calls, such as when the", " interpreter loads extension modules. Among other things, this will enable", " a lazy resolving of symbols when importing a module, if called as", " sys.setdlopenflags(0). To share symbols across extension modules, call as", " sys.setdlopenflags(ctypes.RTLD_GLOBAL). Symbolic names for the flag modules", " can be either found in the ctypes module, or in the DLFCN module. If DLFCN", " is not available, it can be generated from /usr/include/dlfcn.h using the", " h2py script.", " ", " setprofile(...)", " setprofile(function)", " ", " Set the profiling function. It will be called on each function call", " and return. See the profiler chapter in the library manual.", " ", " setrecursionlimit(...)", " setrecursionlimit(n)", " ", " Set the maximum depth of the Python interpreter stack to n. This", " limit prevents infinite recursion from causing an overflow of the C", " stack and crashing Python. The highest possible limit is platform-", " dependent.", " ", " settrace(...)", " settrace(function)", " ", " Set the global debug tracing function. It will be called on each", " function call. See the debugger chapter in the library manual.", "", "DATA", " __stderr__ = ', mode 'w'>", " __stdin__ = ', mode 'r'>", " __stdout__ = ', mode 'w'>", " api_version = 1013", " argv = ['-c', '-f', '/home/stef/.ipython/profile_default/security/kern...", " builtin_module_names = ('__builtin__', '__main__', '_ast', '_bisect', ...", " byteorder = 'little'", " copyright = 'Copyright (c) 2001-2012 Python Software Foundati...ematis...", " displayhook = ", " dont_write_bytecode = False", " exc_value = TypeError(\" is a built-in module\"...", " exec_prefix = '/home/stef/tasks/pywik/env'", " executable = '/home/stef/tasks/pywik/env/bin/python'", " flags = sys.flags(debug=0, py3k_warning=0, division_warn...unicode=0, ...", " float_info = sys.float_info(max=1.7976931348623157e+308, max_...epsilo...", " float_repr_style = 'short'", " hexversion = 34014146", " last_value = AttributeError(\"'module' object has no attribute '__main_...", " long_info = sys.long_info(bits_per_digit=15, sizeof_digit=2)", " maxint = 2147483647", " maxsize = 2147483647", " maxunicode = 1114111", " meta_path = []", " modules = {'ConfigParser': ]", " path_importer_cache = {'': None, '/home/stef/.ipython/extensions': ", " stdin = ', mode 'r'>", " stdout = ", " subversion = ('CPython', '', '')", " version = '2.7.3rc2 (default, Apr 22 2012, 22:35:38) \\n[GCC 4.6.3]'", " version_info = sys.version_info(major=2, minor=7, micro=3, releaseleve...", " warnoptions = []", "", "" ] } ], "prompt_number": 70 }, { "cell_type": "code", "collapsed": false, "input": [ "sys." ], "language": "python", "outputs": [ { "ename": "AttributeError", "evalue": "'module' object has no attribute '__main__'", "output_type": "pyerr", "traceback": [ "\u001b[1;31m---------------------------------------------------------------------------\u001b[0m\n\u001b[1;31mAttributeError\u001b[0m Traceback (most recent call last)", "\u001b[1;32m/home/stef/tasks/pywik/\u001b[0m in \u001b[0;36m\u001b[1;34m()\u001b[0m\n\u001b[1;32m----> 1\u001b[1;33m \u001b[0msys\u001b[0m\u001b[1;33m.\u001b[0m\u001b[0m__main__\u001b[0m\u001b[1;33m,\u001b[0m \u001b[0m__main__\u001b[0m\u001b[1;33m\u001b[0m\u001b[0m\n\u001b[0m", "\u001b[1;31mAttributeError\u001b[0m: 'module' object has no attribute '__main__'" ] } ], "prompt_number": 69 }, { "cell_type": "code", "collapsed": true, "input": [], "language": "python", "outputs": [] } ] } ] }