Re: [Tutor] Potential problem with Game Over 2.0 problem in "Python Programming for the Absolute Beginner, 3rd Ed."
On Tue, Feb 17, 2015 at 3:34 PM, Joel Goldstick wrote: > On Tue, Feb 17, 2015 at 4:05 PM, boB Stepp wrote: >> On Tue, Feb 17, 2015 at 1:47 PM, Dave Angel wrote: >>> On 02/17/2015 02:12 PM, boB Stepp wrote: >> This seems to be the case. On a related note, I wanted to copy and >> paste the author's source code, showing how he generated the large, >> "Game Over", but my Gmail keeps collapsing the white space, making the >> result look like gibberish. So far I cannot find a setting to >> eliminate this undesired behavior. Argh! > > Do you have gmail set to plain text mode? What I just sent out, that showed what I wanted to show, was not plain text, but Google's fixed-width font. Of course, turning that on took away plain text mode. I had a couple of years ago or so (Whenever it was that I started working with Python and interacting with the Tutor list.) installed the Stylish extension to Gmail and set up a plain text, fixed width font. Somehow that font has been removed from my Gmail settings with no known action on my part. I did not notice it until today when I tried to reproduce the ASCII art under discussion in this thread and found that I could not. So apparently I can do plain text, but not fixed width, or I can do fixed width, but not plain text! At least until I come up with a solution. Heavy sighs! -- boB ___ Tutor maillist - Tutor@python.org To unsubscribe or change subscription options: https://mail.python.org/mailman/listinfo/tutor
Re: [Tutor] Potential problem with Game Over 2.0 problem in "Python Programming for the Absolute Beginner, 3rd Ed."
On Tue, Feb 17, 2015 at 4:05 PM, boB Stepp wrote: > On Tue, Feb 17, 2015 at 1:47 PM, Dave Angel wrote: >> On 02/17/2015 02:12 PM, boB Stepp wrote: >> >> See >> https://docs.python.org/3.4/reference/lexical_analysis.html#string-and-bytes-literals >>> >>> >>> At this point in the text he is not talking about raw literal strings. >>> I examined the author's source and he has obviously inserted at least >>> one space between each use of a backslash at the end of a line and the >>> EOL terminating characters. >> >> >> Then he's teaching you wrong. Backslash followed by space is not a valid >> escape sequence, and to do it at the end of line is particularly odious. I >> wouldn't even suggest it in real code, never mind in something that's >> published on paper. > > I guess I am inclined to cut the author some slack here. The point of > his example was NOT to teach escape sequences, but instead show how > using keyboard characters you could create a text picture, in this > instance of a large "Game Over". He at this point was talking about > the print function used with quotes and triple quotes. A little bit > later in this same chapter he talks about escape sequences. The point > of my original post was to point out that because the author is using > a backslash as part of his ASCII art, that unintended consequences > might result. I will admit that I was surprised that the author did > not think of this potential issue and warn the reader of possible > problems, especially as the book is aimed at total beginners. But I > suppose it is difficult to anticipate all possible problems. But sure > enough, my son stumbled into this one! > > [...] > >> I would never intentionally make any trailing whitespace in source code be >> significant. And years ago I used an editor that routinely deleted any such >> invisible characters. From the rest of your message, it looks like IDLE may >> have that behavior. > > This seems to be the case. On a related note, I wanted to copy and > paste the author's source code, showing how he generated the large, > "Game Over", but my Gmail keeps collapsing the white space, making the > result look like gibberish. So far I cannot find a setting to > eliminate this undesired behavior. Argh! Do you have gmail set to plain text mode? > -- > boB > ___ > Tutor maillist - Tutor@python.org > To unsubscribe or change subscription options: > https://mail.python.org/mailman/listinfo/tutor -- Joel Goldstick http://joelgoldstick.com ___ Tutor maillist - Tutor@python.org To unsubscribe or change subscription options: https://mail.python.org/mailman/listinfo/tutor
Re: [Tutor] Potential problem with Game Over 2.0 problem in "Python Programming for the Absolute Beginner, 3rd Ed."
On Tue, Feb 17, 2015 at 3:05 PM, boB Stepp wrote: > This seems to be the case. On a related note, I wanted to copy and > paste the author's source code, showing how he generated the large, > "Game Over", but my Gmail keeps collapsing the white space, making the > result look like gibberish. So far I cannot find a setting to > eliminate this undesired behavior. Argh! I have found the problem. During some previous update or other Google-induced behavior, all of the work I did to have a specific fixed-width font with an extension has apparently been undone. Anyway, here is the snippet of the author's source code that I had intended to send earlier: print( """ _ ___ ___ ___ _ / ___| / | / |/ | | ___| | |/ /| |/ /| /| | | |__ | | _/ ___ | / / |__/ | | | __| | |_| | / / | | / / | | | |___ \_/ /_/ |_| /_/|_| |_| _ _ _ _ _ / _ \ | | / / | ___| | _ \ | | | | | | / / | |__ | |_| | | | | | | | / / | __| | _ / | |_| | | |/ /| |___ | | \ \ \_/ |___/ |_| |_| \_\ """ ) -- boB ___ Tutor maillist - Tutor@python.org To unsubscribe or change subscription options: https://mail.python.org/mailman/listinfo/tutor
Re: [Tutor] Potential problem with Game Over 2.0 problem in "Python Programming for the Absolute Beginner, 3rd Ed."
On Tue, Feb 17, 2015 at 1:47 PM, Dave Angel wrote: > On 02/17/2015 02:12 PM, boB Stepp wrote: > > See > https://docs.python.org/3.4/reference/lexical_analysis.html#string-and-bytes-literals >> >> >> At this point in the text he is not talking about raw literal strings. >> I examined the author's source and he has obviously inserted at least >> one space between each use of a backslash at the end of a line and the >> EOL terminating characters. > > > Then he's teaching you wrong. Backslash followed by space is not a valid > escape sequence, and to do it at the end of line is particularly odious. I > wouldn't even suggest it in real code, never mind in something that's > published on paper. I guess I am inclined to cut the author some slack here. The point of his example was NOT to teach escape sequences, but instead show how using keyboard characters you could create a text picture, in this instance of a large "Game Over". He at this point was talking about the print function used with quotes and triple quotes. A little bit later in this same chapter he talks about escape sequences. The point of my original post was to point out that because the author is using a backslash as part of his ASCII art, that unintended consequences might result. I will admit that I was surprised that the author did not think of this potential issue and warn the reader of possible problems, especially as the book is aimed at total beginners. But I suppose it is difficult to anticipate all possible problems. But sure enough, my son stumbled into this one! [...] > I would never intentionally make any trailing whitespace in source code be > significant. And years ago I used an editor that routinely deleted any such > invisible characters. From the rest of your message, it looks like IDLE may > have that behavior. This seems to be the case. On a related note, I wanted to copy and paste the author's source code, showing how he generated the large, "Game Over", but my Gmail keeps collapsing the white space, making the result look like gibberish. So far I cannot find a setting to eliminate this undesired behavior. Argh! -- boB ___ Tutor maillist - Tutor@python.org To unsubscribe or change subscription options: https://mail.python.org/mailman/listinfo/tutor
Re: [Tutor] Potential problem with Game Over 2.0 problem in "Python Programming for the Absolute Beginner, 3rd Ed."
> Dawson) Game Over 2.0 program in chapter two on page 17. The object of > this program is to do ASCII-style art to generate a large rendition of > "Game Over" using the following characters: "_" , "\" , "|" , and "/" > . When my son tried to do his version, the "Over" portion did not > print correctly. Hi boB, Ah ha. Escape characters. I see what you mean. :P Just to add: there is a "raw" string literal syntax that will turn off escape sequence handling. Using a raw string literal may make it easier to type the value in question. We can use raw literal strings by prepending a 'r' in the front of the string literal. e.g.: ## >>> x = r''' ... this\ ... is\ ... a/ ... test\ ... ''' >>> x '\nthis\\\nis\\\na/\ntest\\\n' >>> print x this\ is\ a/ test\ ## It might be that the question is trying to motivate the use of raw string literals, or teaching about escape sequences. I don't have the book, so I can't say for sure. ___ Tutor maillist - Tutor@python.org To unsubscribe or change subscription options: https://mail.python.org/mailman/listinfo/tutor
Re: [Tutor] Potential problem with Game Over 2.0 problem in "Python Programming for the Absolute Beginner, 3rd Ed."
On 02/17/2015 02:12 PM, boB Stepp wrote: See https://docs.python.org/3.4/reference/lexical_analysis.html#string-and-bytes-literals At this point in the text he is not talking about raw literal strings. I examined the author's source and he has obviously inserted at least one space between each use of a backslash at the end of a line and the EOL terminating characters. Then he's teaching you wrong. Backslash followed by space is not a valid escape sequence, and to do it at the end of line is particularly odious. I wouldn't even suggest it in real code, never mind in something that's published on paper. The docs admit that the invalid escape sequences behave differently than C, in that the backslash is retained. I think it should be a syntax error to have an invalid sequence. If the backslash immediately precedes the newline, then the two characters both get eaten, and the two lines are combined into one. That can be useful if you want to define a string that's too long to fit in your source file. I would never intentionally make any trailing whitespace in source code be significant. And years ago I used an editor that routinely deleted any such invisible characters. From the rest of your message, it looks like IDLE may have that behavior. He did not do this with the "Game" portion of the code, which did not make any use of "\" . When the file is run everything behaves as desired. But if, as my son did, you leave no spaces between the last backslash and the EOL termination characters, then the problem behavior occurs. -- DaveA ___ Tutor maillist - Tutor@python.org To unsubscribe or change subscription options: https://mail.python.org/mailman/listinfo/tutor
Re: [Tutor] Potential problem with Game Over 2.0 problem in "Python Programming for the Absolute Beginner, 3rd Ed."
On Tue, Feb 17, 2015 at 12:43 PM, Danny Yoo wrote:
[...]
> Ah ha. Escape characters. I see what you mean. :P
>
>
> Just to add: there is a "raw" string literal syntax that will turn off
> escape sequence handling. Using a raw string literal may make it
> easier to type the value in question.
>
> We can use raw literal strings by prepending a 'r' in the front of the
> string literal. e.g.:
>
> ##
x = r'''
> ... this\
> ... is\
> ... a/
> ... test\
> ... '''
x
> '\nthis\\\nis\\\na/\ntest\\\n'
print x
>
> this\
> is\
> a/
> test\
> ##
Actually, that is the solution I recommended to my son to use.
> It might be that the question is trying to motivate the use of raw
> string literals, or teaching about escape sequences. I don't have the
> book, so I can't say for sure.
At this point in the text he is not talking about raw literal strings.
I examined the author's source and he has obviously inserted at least
one space between each use of a backslash at the end of a line and the
EOL terminating characters. He did not do this with the "Game" portion
of the code, which did not make any use of "\" . When the file is run
everything behaves as desired. But if, as my son did, you leave no
spaces between the last backslash and the EOL termination characters,
then the problem behavior occurs. Actually, I realize I have a
question:
If I do the following in the Win7 command line Python interpreter:
Python 3.4.2 (v3.4.2:ab2c023a9432, Oct 6 2014, 22:16:31) [MSC v.1600 64 bit (AM
D64)] on win32
Type "help", "copyright", "credits" or "license" for more information.
>>> print("""
... boB\
... Stepp
... """
... )
boB\
Stepp
Here I placed exactly one space between "\" and where I pressed
"Enter". This would be the Game Over 2.0 desired behavior. However, if
I bring up the IDLE Python interpreter and do the exact same thing:
Python 3.4.2 (v3.4.2:ab2c023a9432, Oct 6 2014, 22:16:31) [MSC v.1600
64 bit (AMD64)] on win32
Type "copyright", "credits" or "license()" for more information.
>>> print("""
boB\
Stepp
"""
)
boBStepp
it gives the undesired behavior. I typed exactly the same character
sequences, though IDLE displayed things slightly differently, e.g.,
the command line interpreter put in "..." in several places, where the
IDLE interpreter did not. I am currently scratching my head on these
differences, and am currently guessing that IDLE implements the Python
interpreter somewhat differently than the implementation that occurs
in the Windows command line. Do you have an explanation for these
differences?
--
boB
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[Tutor] Potential problem with Game Over 2.0 problem in "Python Programming for the Absolute Beginner, 3rd Ed."
I know that there have been multiple posts in the past about Michael Dawson's book, "Python Programming for the Absolute Beginner, 3rd ed.". Because of this I thought I might mention something my son encountered this morning. I have finally gotten my son to start working in this book. He came to me with a problem this morning, which he could not figure out when trying to replicate the author's (Michael Dawson) Game Over 2.0 program in chapter two on page 17. The object of this program is to do ASCII-style art to generate a large rendition of "Game Over" using the following characters: "_" , "\" , "|" , and "/" . When my son tried to do his version, the "Over" portion did not print correctly. The top half of "Over" printed first followed by the second half of the word next to it. I don't want to say too much for those working through this book, but the essence of the issue is illustrated by the following: Python 3.4.2 (v3.4.2:ab2c023a9432, Oct 6 2014, 22:16:31) [MSC v.1600 64 bit (AMD64)] on win32 Type "copyright", "credits" or "license()" for more information. >>> print( """ boB Stepp """ ) boB Stepp >>> print( """ boB\ Stepp """ ) boBStepp This led to a discussion with my son about the invisible characters that terminate lines in Window and *nix, escape sequences, etc. Hopefully this might prove helpful to those starting this book without just giving the answer if this problem comes up in their efforts. -- boB ___ Tutor maillist - Tutor@python.org To unsubscribe or change subscription options: https://mail.python.org/mailman/listinfo/tutor
