Re: [Tutor] flow problem with a exercise
From: waynejwer...@gmail.com Date: Fri, 20 Aug 2010 15:07:56 -0500 Subject: Re: [Tutor] flow problem with a exercise To: rwob...@hotmail.com CC: tutor@python.org On Fri, Aug 20, 2010 at 2:48 PM, Roelof Wobben rwob...@hotmail.com wrote: Oke, I don''t understand it complety. return not arg%2 Why use not here ? I think that arg%2 is True not makes it false. What happens when you replace arg with a value? % is modulo division, so it just returns the remainder. 2 % 2 = ? 2%2=0 4 % 2 = ? 4%2=0 7 % 2 = ? 7%2=1 11 % 2 = ? 11%2 =1 What is the truth value of 0 and 1? print 'True' if 0 else 'False' False print 'True' if 1 else 'False' True So what is the outcome of the following? result = 2 % 2 print result, not result if not result: print 'Even' if result: print 'odd' 0 True Even So 1 is True and 0 is False according to Python. Another question. How can I round outcome of a calculation. round ( ( t-32)/1.8) does not work because I get a message that there are two arguments. Outcome = (t-32)/1.8 outcome2 = round (outcome) does not work because the argument must be a string or a number What is the type of t? In [39]: t = 3 In [40]: round((t-32)/1.8) Out[40]: -16.0 In [41]: t = 3.0 In [42]: round((t-32)/1.8) Out[42]: -16.0 Works fine for me. Correct, But I see one wierd thing. round ((42-32)/1.8) gives a output -16.0 but (42-32)/1.8) gives also -16.0 I was expectting that round will give 16 as output because round (32.0) is the same as round (32.0, 0) so there will be 0 decimals. And I see one decimal. Roelof HTH, Wayne ___ Tutor maillist - Tutor@python.org To unsubscribe or change subscription options: http://mail.python.org/mailman/listinfo/tutor
Re: [Tutor] flow problem with a exercise
In [39]: t = 3 In [40]: round((t-32)/1.8) Out[40]: -16.0 In [41]: t = 3.0 In [42]: round((t-32)/1.8) Out[42]: -16.0 Works fine for me. Correct, But I see one wierd thing. round ((42-32)/1.8) gives a output -16.0 but (42-32)/1.8) gives also -16.0 I was expectting that round will give 16 as output because round (32.0) is the same as round (32.0, 0) so there will be 0 decimals. And I see one decimal. The rounding doesn't influence how it's printed. From help(round): round(...) round(number[, ndigits]) - floating point number Round a number to a given precision in decimal digits (default 0 digits). This always returns a floating point number. Precision may be negative. It *rounds* the number to ndigits, not prints. It always returns a floating point number though (not an integer). Since floats are normally represented with at least one trailing digit after the decimal dot, you see a zero. Eg, float(1) 1.0 If you want to get rid of the trailing .0, convert it to an integer: int(round(1.1)) 1 Also consider: round(1.15, 0) 1.0 round(1.15, 1) 1.2 round(1.15, 2) 1.1499 (Note again how the last rounded 1.15 is represented. It's just a representation though, and showing the imprecision you intrinsicaly get when dealing with floating point numbers.) If you really want different behaviour when printing (or using) floating point numbers, perhaps have a look at the decimal module: http://docs.python.org/library/decimal.html ___ Tutor maillist - Tutor@python.org To unsubscribe or change subscription options: http://mail.python.org/mailman/listinfo/tutor
Re: [Tutor] flow problem with a exercise
You need to figure out how to get your email program to do quoting. As it stands, there's no good way to tell what part of the following message was from you, and what part was from wayne, or maybe others. Probably all you need to do is to do a reply-all to the message, and it'll mark the existing text with a symbol. Then make sure everything you type is *not* quoted. Roelof Wobben wrote: From: waynejwer...@gmail.com snip result = 2 % 2 print result, not result if not result: print 'Even' if result: print 'odd' 0 True Even So 1 is True and 0 is False according to Python. No, True is a specific object that differs from all other objects. Likewise False. However, other objects, including especially integers, lists, and strings, can be used in a boolean context, and there are specific rules that decide whether a given object will be used as true (lowercase) or false. For integers values, all nonzero items are considered true, while zero is considered false. Another question. How can I round outcome of a calculation. round ( ( t-32)/1.8) does not work because I get a message that there are two arguments. Outcome = (t-32)/1.8 outcome2 = round (outcome) does not work because the argument must be a string or a number What is the type of t? In [39]: t = 3 In [40]: round((t-32)/1.8) Out[40]: -16.0 In [41]: t = 3.0 In [42]: round((t-32)/1.8) Out[42]: -16.0 Works fine for me. Correct, But I see one wierd thing. round ((42-32)/1.8) gives a output -16.0 but (42-32)/1.8) gives also -16.0 I was expectting that round will give 16 as output because round (32.0) is the same as round (32.0, 0) so there will be 0 decimals. And I see one decimal. Roelof HTH, Wayne You're confusing the operation of round() with the operation of converting to a string for printing. Round changes a floating point (binary) value to have a certain quantization, which approximates what you might want to print. It does not, however, affect the way print will subsequently deal with that floating point number. It's no different than when you use a numeric literal with varying amounts of apparent precision. x = 4.2 x = 4.20 x = 4.20 all produce precisely the same floating point object. DaveA ___ Tutor maillist - Tutor@python.org To unsubscribe or change subscription options: http://mail.python.org/mailman/listinfo/tutor
Re: [Tutor] flow problem with a exercise
Subject: Re: [Tutor] flow problem with a exercise From: evert@gmail.com Date: Sat, 21 Aug 2010 12:39:05 +0200 CC: tutor@python.org To: rwob...@hotmail.com In [39]: t = 3 In [40]: round((t-32)/1.8) Out[40]: -16.0 In [41]: t = 3.0 In [42]: round((t-32)/1.8) Out[42]: -16.0 Works fine for me. Correct, But I see one wierd thing. round ((42-32)/1.8) gives a output -16.0 but (42-32)/1.8) gives also -16.0 I was expectting that round will give 16 as output because round (32.0) is the same as round (32.0, 0) so there will be 0 decimals. And I see one decimal. The rounding doesn't influence how it's printed. From help(round): round(...) round(number[, ndigits]) - floating point number Round a number to a given precision in decimal digits (default 0 digits). This always returns a floating point number. Precision may be negative. It *rounds* the number to ndigits, not prints. It always returns a floating point number though (not an integer). Since floats are normally represented with at least one trailing digit after the decimal dot, you see a zero. Eg, float(1) 1.0 If you want to get rid of the trailing .0, convert it to an integer: int(round(1.1)) 1 Also consider: round(1.15, 0) 1.0 round(1.15, 1) 1.2 round(1.15, 2) 1.1499 (Note again how the last rounded 1.15 is represented. It's just a representation though, and showing the imprecision you intrinsicaly get when dealing with floating point numbers.) If you really want different behaviour when printing (or using) floating point numbers, perhaps have a look at the decimal module: http://docs.python.org/library/decimal.html Oke, Thank you. Learned another thing about Python. Roelof ___ Tutor maillist - Tutor@python.org To unsubscribe or change subscription options: http://mail.python.org/mailman/listinfo/tutor
Re: [Tutor] flow problem with a exercise
Roelof Wobben rwob...@hotmail.com wrote Others have pointed out the lack of indentation. I'll point out some shortcuts you can use... def is_even(argument): remainder= argument%2 if remainder == 0 : return True else : return False You can abbreviate this to just def is_even(arg): return not arg%2 def is_odd(argument): uitkomst=is_even(argument) return uitkomst and this to: def is_odd(arg): return not is_even(arg) HTH, -- Alan Gauld Author of the Learn to Program web site http://www.alan-g.me.uk/ ___ Tutor maillist - Tutor@python.org To unsubscribe or change subscription options: http://mail.python.org/mailman/listinfo/tutor
Re: [Tutor] flow problem with a exercise
Oke, I don''t understand it complety. return not arg%2 Why use not here ? I think that arg%2 is True not makes it false. Another question. How can I round outcome of a calculation. round ( ( t-32)/1.8) does not work because I get a message that there are two arguments. Outcome = (t-32)/1.8 outcome2 = round (outcome) does not work because the argument must be a string or a number Roelof ___ Tutor maillist - Tutor@python.org To unsubscribe or change subscription options: http://mail.python.org/mailman/listinfo/tutor
Re: [Tutor] flow problem with a exercise
On Fri, Aug 20, 2010 at 2:48 PM, Roelof Wobben rwob...@hotmail.com wrote: Oke, I don''t understand it complety. return not arg%2 Why use not here ? I think that arg%2 is True not makes it false. What happens when you replace arg with a value? % is modulo division, so it just returns the remainder. 2 % 2 = ? 4 % 2 = ? 7 % 2 = ? 11 % 2 = ? What is the truth value of 0 and 1? print 'True' if 0 else 'False' print 'True' if 1 else 'False' So what is the outcome of the following? result = 2 % 2 print result, not result if not result: print 'Even' if result: print 'odd' Another question. How can I round outcome of a calculation. round ( ( t-32)/1.8) does not work because I get a message that there are two arguments. Outcome = (t-32)/1.8 outcome2 = round (outcome) does not work because the argument must be a string or a number What is the type of t? In [39]: t = 3 In [40]: round((t-32)/1.8) Out[40]: -16.0 In [41]: t = 3.0 In [42]: round((t-32)/1.8) Out[42]: -16.0 Works fine for me. HTH, Wayne ___ Tutor maillist - Tutor@python.org To unsubscribe or change subscription options: http://mail.python.org/mailman/listinfo/tutor
Re: [Tutor] flow problem with a exercise
Please use ReplyAll when responding to posts from the tutor list. I don''t understand it complety. return not arg%2 Why use not here ? I think that arg%2 is True not makes it false. For an even number arg % 2 will be 0 which Python considers to be False. So for a True result when arg%2 is zero, you must negate the logic Another question. How can I round outcome of a calculation. round ( ( t-32)/1.8) does not work because I get a message that there are two arguments. Check your code because thre is only one arg here. Therefore the actual code giving the error must be different in some way. Outcome = (t-32)/1.8 outcome2 = round (outcome) does not work because the argument must be a string or a number Assuming t is a number the outcome will be a number so it should work. It helps if you cut n paste the real code and the real error message, do not just summarise. Python error messages are extremely helpful, but only if we can see them. Alan G. ___ Tutor maillist - Tutor@python.org To unsubscribe or change subscription options: http://mail.python.org/mailman/listinfo/tutor
Re: [Tutor] flow problem with a exercise
On Thu, Aug 19, 2010 at 3:01 PM, Roelof Wobben rwob...@hotmail.com wrote: Hello, I have this exercise: Now write the function is_odd(n) that returns True when n is odd and Falseotherwise. Include doctests for this function as you write it. Finally, modify it so that it uses a call to is_even to determine if its argument is an odd integer. So I thought of this : def is_even(argument): remainder= argument%2 if remainder == 0 : return True else : return False def is_odd(argument): uitkomst=is_even(argument) return uitkomst NOTE that your return statement is not indented properly. It must line up under uitkomst even=is_odd(1) ; if even==True : print Even getal if even==False: print Oneven getal But now I get this error message : return uitkomst Syntax error : return outside function. In my opinon even calls is_odd , then uitkomst calls is_even which gives a true or false to uitkomst. So return uitkomst gives the outcome to even. But the intepreter thinks otherwise. I work on a Win7 machine with Python 2.7 Roelof ___ Tutor maillist - Tutor@python.org To unsubscribe or change subscription options: http://mail.python.org/mailman/listinfo/tutor -- Joel Goldstick ___ Tutor maillist - Tutor@python.org To unsubscribe or change subscription options: http://mail.python.org/mailman/listinfo/tutor
Re: [Tutor] flow problem with a exercise
On Thu, Aug 19, 2010 at 2:01 PM, Roelof Wobben rwob...@hotmail.com wrote: snip def is_odd(argument): uitkomst=is_even(argument) return uitkomst even=is_odd(1) ; if even==True : print Even getal if even==False: print Oneven getal But now I get this error message : return uitkomst Syntax error : return outside function. Check your indention. In the email your return is at a different level than your function. Always use 4 spaces. If your editor can't convert, you need a better editor! In my opinon even calls is_odd , then uitkomst calls is_even which gives a true or false to uitkomst. So return uitkomst gives the outcome to even. But the intepreter thinks otherwise. Well, good thing opinions don't count for much when talking to a computer ;) You are correct that uitkomst contains the result of is_even, but your return is on a different indention level. Whitespace is significant here. If I were you, I would define is_odd this way: def is_odd(argument): uitkomst = not is_even(argument) return uitkomst I work on a Win7 machine with Python 2.7 Good job providing both the traceback and your system. They make every problem easier to debug. HTH, Wayne ___ Tutor maillist - Tutor@python.org To unsubscribe or change subscription options: http://mail.python.org/mailman/listinfo/tutor
Re: [Tutor] flow problem with a exercise
On 8/19/10, Roelof Wobben rwob...@hotmail.com wrote: Hello, I have this exercise: Now write the function is_odd(n) that returns True when n is odd and False otherwise. Include doctests for this function as you write it. Finally, modify it so that it uses a call to is_even to determine if its argument is an odd integer. So I thought of this : def is_even(argument): remainder= argument%2 if remainder == 0 : return True else : return False def is_odd(argument): uitkomst=is_even(argument) return uitkomst The above line, the return statement, has to be indented; it did not appear to be in your email. Also, maybe you want to return the opposite of is_even in is_odd? Right now it looks like you are going to get something like: is_odd(3): is_even(3)=False, so is_odd(3) will echo that False. Maybe return !uitkomst instead. I could have read it wrong, though. even=is_odd(1) ; if even==True : print Even getal if even==False: print Oneven getal But now I get this error message : return uitkomst Syntax error : return outside function. In my opinon even calls is_odd , then uitkomst calls is_even which gives a true or false to uitkomst. So return uitkomst gives the outcome to even. But the intepreter thinks otherwise. I work on a Win7 machine with Python 2.7 Roelof -- Have a great day, Alex (msg sent from GMail website) mehg...@gmail.com; http://www.facebook.com/mehgcap ___ Tutor maillist - Tutor@python.org To unsubscribe or change subscription options: http://mail.python.org/mailman/listinfo/tutor
Re: [Tutor] flow problem with a exercise
Roelof Wobben wrote: snip def is_odd(argument): uitkomst=is_even(argument) return uitkomst snip You forgot to indent the return statement to match the other statement(s) in the function. DaveA ___ Tutor maillist - Tutor@python.org To unsubscribe or change subscription options: http://mail.python.org/mailman/listinfo/tutor
