Re: Interesting list Validity (True/False)
Just an update of my output after Carsten and company's advice: C:\Python25\rg.py>help.py -h help.py Version 1.0 Copyright RDEG (c) 2007 Options : -h, --help -- display this message Progam Exit (0) C:\Python25\rg.py>help.py -i print arg ['-i'] type(arg): arg is True? False help.py version 1.0 Copyright RDEG (c) 2007 ['-i'] is an unrecognized option. Progam Exit (0) C:\Python25\rg.py>help.py -i help.py version 1.0 Copyright RDEG (c) 2007 ['-i'] is an unrecognized option. Progam Exit (0) C:\Python25\rg.py>help.py No Option provided help.py version 1.0 Copyright RDEG (c) 2007 No Option is an unrecognized option. Progam Exit (0) Thanks again. -- http://mail.python.org/mailman/listinfo/python-list
Re: Interesting list Validity (True/False)
On May 11, 5:19 pm, Carsten Haese <[EMAIL PROTECTED]> wrote: > On Fri, 2007-05-11 at 14:12 -0700, [EMAIL PROTECTED] wrote: > > However, how would you test for the falsness of the object arg? > > if not arg: ># stuff > > -- > Carsten Haesehttp://informixdb.sourceforge.net I think that is the ticket Carsten! Thanks for all the good information all y'all. -- http://mail.python.org/mailman/listinfo/python-list
Re: Interesting list Validity (True/False)
On May 11, 5:12 pm, [EMAIL PROTECTED] wrote: > On May 11, 5:07 pm, Carsten Haese <[EMAIL PROTECTED]> wrote: > > > > > > > On Fri, 2007-05-11 at 12:28 -0700, [EMAIL PROTECTED] wrote: > > > Hello all, > > > > First let me appologise if this has been answered but I could not find > > > an acurate answer to this interesting problem. > > > > If the following is true: > > > C:\Python25\rg.py>python > > > Python 2.5.1 (r251:54863, Apr 18 2007, 08:51:08) [MSC v.1310 32 > > > bit (Intel)] on > > > win32 > > > Type "help", "copyright", "credits" or "license" for more > > > information. > > > >>> [] == [] > > > True > > > >>> ['-o'] == [] > > > False > > > >>> ['-o'] == False > > > False > > > Your confusion stems from the fact that for a given object, the answer > > to the following three questions can be vastly different: > > a) Is the object identical to True? > > b) Is the object equal to True? > > c) Is the object considered to be True in an "if" statement? > > > Observe: > > > >>> def check_trueness(obj): > > > ...if obj is True: print repr(obj), "is identical to True." > > ...else: print repr(obj), "is not identical to True." > > ...if obj == True: print repr(obj), "is equal to True." > > ...else: print repr(obj), "is not equal to True." > > ...if obj: print repr(obj), "is considered to be True by if." > > ...else: print repr(obj), "is not considered to be True by if." > > ...>>> check_trueness(True) > > > True is identical to True. > > True is equal to True. > > True is considered to be True by if.>>> check_trueness(1) > > > 1 is not identical to True. > > 1 is equal to True. > > 1 is considered to be True by if.>>> check_trueness([1]) > > > [1] is not identical to True. > > [1] is not equal to True. > > [1] is considered to be True by if.>>> check_trueness([]) > > > [] is not identical to True. > > [] is not equal to True. > > [] is not considered to be True by if. > > > Testing whether an object is equal to True is a much stronger test than > > whether it is considered to be True in an 'if' statement, and the test > > for identity is stronger still. Testing whether an object is equal to > > True or identical to True is useless in most Python programs. > > > So, rather than doing this: > > > if thing==True: > ># blah > > > Just do this: > > > if thing: > ># blah > > > Hope this helps, > > > -- > > Carsten Haesehttp://informixdb.sourceforge.net-Hide quoted text - > > > - Show quoted text - > > Thanks Carsten (& all), I will give the if thing: # blah trick. I > guess I am starting to seem my own confusion. As Grant mentioned, I > was comparing ['-o'] to True which of course is False :o) > > However, how would you test for the falsness of the object arg?- Hide quoted > text - > > - Show quoted text - Would that be arg is not True: # blah.? -- http://mail.python.org/mailman/listinfo/python-list
Re: Interesting list Validity (True/False)
On May 11, 5:07 pm, Carsten Haese <[EMAIL PROTECTED]> wrote: > On Fri, 2007-05-11 at 12:28 -0700, [EMAIL PROTECTED] wrote: > > Hello all, > > > First let me appologise if this has been answered but I could not find > > an acurate answer to this interesting problem. > > > If the following is true: > > C:\Python25\rg.py>python > > Python 2.5.1 (r251:54863, Apr 18 2007, 08:51:08) [MSC v.1310 32 > > bit (Intel)] on > > win32 > > Type "help", "copyright", "credits" or "license" for more > > information. > > >>> [] == [] > > True > > >>> ['-o'] == [] > > False > > >>> ['-o'] == False > > False > > Your confusion stems from the fact that for a given object, the answer > to the following three questions can be vastly different: > a) Is the object identical to True? > b) Is the object equal to True? > c) Is the object considered to be True in an "if" statement? > > Observe: > > >>> def check_trueness(obj): > > ...if obj is True: print repr(obj), "is identical to True." > ...else: print repr(obj), "is not identical to True." > ...if obj == True: print repr(obj), "is equal to True." > ...else: print repr(obj), "is not equal to True." > ...if obj: print repr(obj), "is considered to be True by if." > ...else: print repr(obj), "is not considered to be True by if." > ...>>> check_trueness(True) > > True is identical to True. > True is equal to True. > True is considered to be True by if.>>> check_trueness(1) > > 1 is not identical to True. > 1 is equal to True. > 1 is considered to be True by if.>>> check_trueness([1]) > > [1] is not identical to True. > [1] is not equal to True. > [1] is considered to be True by if.>>> check_trueness([]) > > [] is not identical to True. > [] is not equal to True. > [] is not considered to be True by if. > > Testing whether an object is equal to True is a much stronger test than > whether it is considered to be True in an 'if' statement, and the test > for identity is stronger still. Testing whether an object is equal to > True or identical to True is useless in most Python programs. > > So, rather than doing this: > > if thing==True: ># blah > > Just do this: > > if thing: ># blah > > Hope this helps, > > -- > Carsten Haesehttp://informixdb.sourceforge.net- Hide quoted text - > > - Show quoted text - Thanks Carsten (& all), I will give the if thing: # blah trick. I guess I am starting to seem my own confusion. As Grant mentioned, I was comparing ['-o'] to True which of course is False :o) However, how would you test for the falsness of the object arg? -- http://mail.python.org/mailman/listinfo/python-list
Re: Interesting list Validity (True/False)
On May 11, 4:32 pm, Grant Edwards <[EMAIL PROTECTED]> wrote: > On Fri, May 11, 2007 at 01:20:44PM -0700, [EMAIL PROTECTED] > wrote: > > > On May 11, 3:55 pm, Grant Edwards <[EMAIL PROTECTED]> wrote: > > > You got those results because that's what your program does. > > > > Were you intending it to do something else? If so, you're > > > going to have to explain what you wanted, because we can't > > According to my output, it seems that arg is False even when I > > give an option of '-o' which according to the book should be > > True. No? > > '-o' is not equal to True. However, that does not mean it > evaluates to false when tested by an if or while statement. > > > If arg == ['-o'] then shouldn't arg == True return True and > > skip the if? > > No. See the folloing link regarding the "truth value" of an > object: > > http://docs.python.org/lib/truth.html > > There are many objects other than True that evaluate to "true" > in the context of an if/while statement. Just because an > objecty has a "true" truth-value doesn't mean that it is equal > to the True object. > > -- > Grant Edwards grante Yow! Why don't you ever > at enter any CONTESTS, >visi.comMarvin?? Don't you know >your own ZIPCODE? OK. Then how would you differenciate between a call with an option versus one without (e.g. help.py -o (where arg == ['-o']) Vs. help.py (where arg == []))? -- http://mail.python.org/mailman/listinfo/python-list
Re: Interesting list Validity (True/False)
On May 11, 2:28 pm, [EMAIL PROTECTED] wrote: > > > > > > > Hello all, > > > First let me appologise if this has been answered but I could not find > > an acurate answer to this interesting problem. > > > If the following is true: > > C:\Python25\rg.py>python > > Python 2.5.1 (r251:54863, Apr 18 2007, 08:51:08) [MSC v.1310 32 > > bit (Intel)] on > > win32 > > Type "help", "copyright", "credits" or "license" for more > > information. > > >>> [] == [] > > True > > >>> ['-o'] == [] > > False > > >>> ['-o'] == False > > False > > > Then why do I get the following results: > > C:\Python25\rg.py>help.py -o > > print arg ['-o'] > > type(arg): > > arg is True? False > > help.py version 1.0 Copyright RDEG (c) 2007 > > ['-o'] is an unrecognized option. > > Progam Exit (0) > > > > > import sys > > > _ver_ = 1.00 > > > if '-h' in sys.argv or '--help' in sys.argv: > > print > > print "help.py Version", _ver_, "Copyright RDEG (c) 2007" > > print ''' > > > Options : -h, --help -- display this message > > Progam Exit (0)''' > > sys.exit(0) > > else: > > arg = sys.argv[1:] > > print 'print arg', arg > > print 'type(arg):', type(arg) > > print 'arg is True?', arg == True > > print "help.py version", _ver_, "Copyright RDEG (c) 2007" > > print "", arg, "is an unrecognized option." > > print "Progam Exit (0)" > > sys.exit(0) > > > I hope this helps (I have tried to post this twice already but it seems to be going somewhere else) you help me. What I would like to happen is: else: arg = sys.argv[1:] print 'print arg', arg print 'type(arg):', type(arg) print 'arg is True?', arg == True if arg != True: print "No Option Provided" print "help.py version", _ver_, "Copyright RDEG (c) 2007" print "", arg, "is an unrecognized option." print "Progam Exit (0)" sys.exit(0) But as you can see by my output ['-o'] seems to be False as well as [] so the if happens regardless. According to the "Book", ['-o'] should return True which should fail the if, no? -- http://mail.python.org/mailman/listinfo/python-list
Interesting list Validity (True/False)
Hello all, First let me appologise if this has been answered but I could not find an acurate answer to this interesting problem. If the following is true: C:\Python25\rg.py>python Python 2.5.1 (r251:54863, Apr 18 2007, 08:51:08) [MSC v.1310 32 bit (Intel)] on win32 Type "help", "copyright", "credits" or "license" for more information. >>> [] == [] True >>> ['-o'] == [] False >>> ['-o'] == False False >>> Then why do I get the following results: C:\Python25\rg.py>help.py -o print arg ['-o'] type(arg): arg is True? False help.py version 1.0 Copyright RDEG (c) 2007 ['-o'] is an unrecognized option. Progam Exit (0) import sys _ver_ = 1.00 if '-h' in sys.argv or '--help' in sys.argv: print print "help.py Version", _ver_, "Copyright RDEG (c) 2007" print ''' Options : -h, --help -- display this message Progam Exit (0)''' sys.exit(0) else: arg = sys.argv[1:] print 'print arg', arg print 'type(arg):', type(arg) print 'arg is True?', arg == True print "help.py version", _ver_, "Copyright RDEG (c) 2007" print "", arg, "is an unrecognized option." print "Progam Exit (0)" sys.exit(0) -- http://mail.python.org/mailman/listinfo/python-list
Re: preferred windows text editor?
On May 9, 3:30 pm, Trent Mick <[EMAIL PROTECTED]> wrote: > There is an ActivePython 2.5.1 > now:http://www.activestate.com/products/activepython/ > > You should give Komodo Edit a try > too:http://www.activestate.com/products/komodo_edit/ Thanks for the heads up Trent. -- http://mail.python.org/mailman/listinfo/python-list
Re: preferred windows text editor?
On May 9, 2:06 pm, "T. Crane" <[EMAIL PROTECTED]> wrote: > Right now I'm using Notepad++. What are other people using? > > trevis I am very noob to this Python game and currently (I was using ActivePython and then IDLE) I have been using a combination of Notepad2 and the interpreter (Python 2.5) on a Windblows X[crement]P[roblem] SP2 machine. Get Notepad2 http://www.flos-freeware.ch/notepad2.html I like IDLE but it seems to stop working after the first few times and I would then re-install it and it would work a few times more. ActivePython was cool but I could not find a version of it that used Python 2.5 (as far as I can see, it only uses 2.4) Notepad2 allows you to launch your script directly from the editor (just like IDLE) and has configurable code highlighting. And it is FREE. -- http://mail.python.org/mailman/listinfo/python-list
Re: preferred windows text editor?
On May 9, 2:06 pm, "T. Crane" <[EMAIL PROTECTED]> wrote: > Right now I'm using Notepad++. What are other people using? I am very noob to this Python game (though it has been around since 1995 me thinks) and currently (I was using ActivePython and then IDLE) I have been using a combination of Notepad2 and the interpreter (Python 2.5) on a Windblows X[crement]P[roblem] SP2 machine. http://www.flos-freeware.ch/notepad2.html I like IDLE but it seems to stop working after the first few times and I would then re-install it and it would work a few times more. ActivePython was cool but I could not find a version of it that used Python 2.5 (as far as I can see, it only uses 2.4) Notepad2 allows you to launch your script directly from the editor (just like IDLE) and has configurable code highlighting. And it is FREE. -- http://mail.python.org/mailman/listinfo/python-list
Re: preferred windows text editor?
On May 9, 2:06 pm, "T. Crane" <[EMAIL PROTECTED]> wrote: > Right now I'm using Notepad++. What are other people using? I am very noob to this Python game (though it has been around since 1995 me thinks) and currently (I was using ActivePython and then IDLE) I have been using a combination of Notepad2 http://www.flos- freeware.ch/notepad2.html and the interpreter (Python 2.5) on a Windblows X[crement]P[roblem] SP2 machine. I like IDLE but it seems to stop working after the first few times and I would then re-install it and it would work a few times more. ActivePython was cool but I could not find a version of it that used Python 2.5 (as far as I can see, it only uses 2.4) Notepad2 allows you to launch your script directly from the editor (just like IDLE) and has configurable code highlighting. And it is FREE. -- http://mail.python.org/mailman/listinfo/python-list
