[Tutor] Executing "if :" function on terminal
Dear Tutor,
i have just started learning python. I have repeatedly hit a road
block on my mac os terminal . Everytime i use the "if :" command i
get syntax errors. i do not see any errors on text editor i am
following instructions from a book
Original input on editor
>>> a=2
>>> if a==2 :
print("correct")
Last login: Tue Sep 5 15:43:03 on ttys000
Solariss-MacBook:~ Solaris$
/var/folders/Db/DbSciGOcFmyQ3L+HyzOb5E+++TI/-Tmp-/Cleanup\ At\
Startup/test-526290211.381.py.command ; exit;
File "/Users/Solaris/Desktop/test.py", line 1
Python 3.0.1 (r301:69597, Feb 14 2009, 19:03:52)
^
SyntaxError: invalid syntax
logout
[Process completed]
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Re: [Tutor] Executing "if :" function on terminal
On 05/09/17 08:56, Nathan Kckaiyer wrote:
> i have just started learning python. I have repeatedly hit a road
> block on my mac os terminal . Everytime i use the "if :" command i
> get syntax errors.
The problem is that you are somehow executing the Python
interpreter prompt in the interpreter. WE need to know exactly how you
are running the code.
Its possible you are trying to execute the shell window of IDLE (or some
other IDE) or that you are copy/pasting too much code from one window to
another. But its impossible to guess.
You need to tell us *exactly* how you run your code.
What tools are you using? What buttons/menus you use etc.
a=2
if a==2 :
> print("correct")
So far so good. That looks like you are typing into the
interactive mode of the Python interpreter. Now if you
just hit Return you should see "correct" being printed
on the screen.
> Solariss-MacBook:~ Solaris$
> /var/folders/Db/DbSciGOcFmyQ3L+HyzOb5E+++TI/-Tmp-/Cleanup\ At\
> Startup/test-526290211.381.py.command ; exit;
> File "/Users/Solaris/Desktop/test.py", line 1
> Python 3.0.1 (r301:69597, Feb 14 2009, 19:03:52)
> ^
> SyntaxError: invalid syntax
But this looks like an OS terminal of some kind trying
to execute a file called test.py
But that file does not contain the Python code above,
it includes the header printed by the interpreter in
interactive mode. That is not executable code and so
Python complains.
test.py should only contain:
a=2
if a==2 :
print("correct")
and nothing else.
HTH
--
Alan G
Author of the Learn to Program web site
http://www.alan-g.me.uk/
http://www.amazon.com/author/alan_gauld
Follow my photo-blog on Flickr at:
http://www.flickr.com/photos/alangauldphotos
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[Tutor] I want to display Integral symbols
I have been trying to display mathematics symbols on my Tkinter (using Python) project, but was not successful .I am trying to compute integrals on my Tkinter project and will like to display this image on my tkinter:∫2xdx. Jupiter can display that symbol using sympy, but I can not display it in my Tkinter. Any help? ___ Tutor maillist - Tutor@python.org To unsubscribe or change subscription options: https://mail.python.org/mailman/listinfo/tutor
[Tutor] Help With Python Tasks
Dear Sir or Madam I was wondering if you can help me please with these computer science tasks as I don’t know where to start: First Task Write code do the following things involving strings. Wherever possible, you should try to incorporate functions/procedures, although they are not appropriate for all tasks. Print a list of 20 random numbers one after the other vertically on the screen. Half way through, use a user input request to pause printing until input is received. Ask a user to enter two numbers, one after the other. Your code should validate that you receive numbers and prompt the user appropriately. For the: first number, use try-except to ensure you have a floating point number; place a comment in you code about how this works second number, use .isnumeric() to check you have an integer; place a comment in your code to explain why this only works for integers Use a forced type conversion to turn both numbers into floats, divided one by the other and print the answer to 2 d.p. You code should keep on asking for numbers until two have been received. Ask the user to input a true/false value and convert the input to a Boolean (hint: I don’t think you can do a forced type conversion for this…) Second Task Write a menu system based on functions where the main program loop is only 2 lines long Write a simple calculator program based around a menu loop. You should be able to enter ‘number 1’ and ‘number 2’ which will be displayed on the screen every time the menu is redisplayed’; there should also be a clear screen function used to avoid the screen getting too cluttered. The calculator menu should allow the user to: enter values for ‘number 1’ and ‘number 2’ add ‘number 1’ and ‘number 2’ subtract ‘number 2’ from ‘number 1’ multiply ‘number 1’ and ‘number 2’ divide ‘number 1’ by ‘number 2’ exit cleanly You program must display an answer that the user can read after each calculation. I would appreciate your help so much as I need to have a finished copy of this code by tomorrow late morning ! Kind Regards Miss Hardy ___ Tutor maillist - Tutor@python.org To unsubscribe or change subscription options: https://mail.python.org/mailman/listinfo/tutor
Re: [Tutor] I want to display Integral symbols
On 05/09/17 14:29, edmundo pierre via Tutor wrote: > I have been trying to display mathematics symbols on my Tkinter (using > Python) project, > but was not successful So show us what you did. Its hard to figure out what's gone wrong when we can't see your code. And that includes telling us what kind of widget you are trying to display this on. A Label? a Text? a Canvas? Any of those are candidates but all have different ways of doing it. > .I am trying to compute integrals on my Tkinter project and will like to > display this image on my tkinter: > ∫2xdx. Are you trying to display an image? Or are you trying to display that as text? If text you need to pick the right font, one that has the integral sign included. You will also likely need to do a fair bit of tweaking with font sizes and line spacing. > Jupiter can display that symbol using sympy,> I can not display it in my > Tkinter. We need more information. As a minimum: Which OS are you using? Which Python version? (and distribution if it includes Jupiter) What UI widget are you using? Are you displaying an image or text? If text which font are you using? Finally what does your code look like? What error messages(in full) do you get(if any) in the console? -- Alan G Author of the Learn to Program web site http://www.alan-g.me.uk/ http://www.amazon.com/author/alan_gauld Follow my photo-blog on Flickr at: http://www.flickr.com/photos/alangauldphotos ___ Tutor maillist - Tutor@python.org To unsubscribe or change subscription options: https://mail.python.org/mailman/listinfo/tutor
Re: [Tutor] Help With Python Tasks
On 05/09/17 19:25, Ruth Hardy wrote: > I was wondering if you can help me please with these computer science tasks We can help, but we won;t do them for you. > First Task > > Write code do the following things involving strings. Wherever possible, > you should try to incorporate functions/procedures, > > Print a list of 20 random numbers one after the other vertically on the > screen. There are (at least) two ways to do this. One very easy but laborious, the other much shorter and quicker. Do you know what they are? Can you print 20 numbers (forget random for now) on the screen? > Half way through, use a user input request to pause printing until > input is received. Do you know how to read user input? > Ask a user to enter two numbers, one after the other. This is slightly ambiguous, but I'd assume they mean you should ask for input twice. Do you know how to store user input into a variable? Do you know how to convert user input to a number? > Your code should validate that you receive numbers and > prompt the user appropriately. Do you know how to validate/check that the received input is a number? (there are several ways to do this, I'm not sure how they expect you to tackle it, it depends on what you've been taught so far) For the: > first number, use try-except to ensure you have a floating point number; OK, That answers my question. You can use try/except to check the number is valid... > place a comment in you code about how this works > second number, use .isnumeric() to check you have an integer; OK, They tell you what to do here. Personally I don;t like the isnumeric() technique but its what they want you to do so do it... > Use a forced type conversion to turn both numbers into floats, >divided one > by the other and print the answer to 2 d.p. Do you know how to print a number so it shows two dp? > You code should keep on asking for numbers until two have been received. OK, Lets just get it working for a single pair of numbers first. Done that? Good, so now wrap it in a loop. What kind of loop will work here? > Ask the user to input a true/false value and convert th> input to a Boolean > (hint: I don’t think you can do a forced > type conversion for this…) The hint is correct. How would you do it without a type conversion? > Second Task Let's leave this task to another email. See if you can answer the questions above. If you can you should be able to join the bits together to get the task completed. If not come back to us with specific issues sand we'll explain a bit more. Show us your code plus any error messages you get. HTH -- Alan G Author of the Learn to Program web site http://www.alan-g.me.uk/ http://www.amazon.com/author/alan_gauld Follow my photo-blog on Flickr at: http://www.flickr.com/photos/alangauldphotos ___ Tutor maillist - Tutor@python.org To unsubscribe or change subscription options: https://mail.python.org/mailman/listinfo/tutor
[Tutor] Select a string
Hello all, I am trying to write a program for a programming class that finds the number of a specific string (bob) in a string of characters. I am using one of the sample strings they give me and it should find 2 instances of bob but my script returns 0. Since they want it to find 2 from the bobob in the string using "bob in s" doesn't work (it only returns 1). My eyes are crossing looking at the code, can someone give me a hint on what I am missing that causes this to not give me the correct answer of 2. #!/usr/bin/env python3 s = 'azcbobobegghakl' count = 0 theo = False firstb = False for i in s: if i == 'b': firstb == True if (i == 'b') and (theo == True): count += 1 if (i =='o') and (firstb == True): theo = True if (i != 'b') and (i != 'o'): theo = False firstb = False print(count) Thanks, Pat ___ Tutor maillist - Tutor@python.org To unsubscribe or change subscription options: https://mail.python.org/mailman/listinfo/tutor
Re: [Tutor] Select a string
Pat Martin writes: > My eyes are crossing looking at the code, can someone give me a hint > on what I am missing that causes this to not give me the correct > answer of 2. It's good to admit that looking at the code has ceased to help :-) So, try a different approach. Without using the code, can you describe your algorithm? Make a pseudo-code description of how you expect to transform the input to the output. For example, I might describe the algorithm for reversing a text string:: * Given a text string named ‘input_text’ * Set the output, named ‘output_text’, to the value "". * Set the index (named ‘index’) to the character length of ‘input_text’. * While ‘index’ is greater than 0: * Subtract 1 from ‘index’. * Get the character at index ‘index’ of ‘input_text’, assign the name ‘input_char’ to that character. * Append ‘input_char’ to ‘output_text’. * Return the value of ‘output_text’. Can you describe your algorithm that way, so we can see what is your intention for the code? -- \ “Faith is the determination to remain ignorant in the face of | `\ all evidence that you are ignorant.” —Shaun Mason | _o__) | Ben Finney ___ Tutor maillist - Tutor@python.org To unsubscribe or change subscription options: https://mail.python.org/mailman/listinfo/tutor
Re: [Tutor] Select a string
On 05Sep2017 22:34, Pat Martin wrote: I am trying to write a program for a programming class that finds the number of a specific string (bob) in a string of characters. I am using one of the sample strings they give me and it should find 2 instances of bob but my script returns 0. Since they want it to find 2 from the bobob in the string using "bob in s" doesn't work (it only returns 1). My eyes are crossing looking at the code, can someone give me a hint on what I am missing that causes this to not give me the correct answer of 2. #!/usr/bin/env python3 s = 'azcbobobegghakl' count = 0 theo = False firstb = False for i in s: if i == 'b': firstb == True This line is a boolean expression using "==", not an assignment using "=". As a consequence firstb is never set to True and the rest of the logic never fires. It is legal in Python to just put an expression on a line. It is usually worth putting in print() calls to debug things like this. I put: print(i, firstb, theo, count) at the start of the loop and learned that firstb never becomes true. I also put the same print statement at the bottom. The advantage of hte above print statement is that it shows you the character from the string along with each set of values. That way you can scan down the output to the "bob" part and look for correct behaviour. I that hadn't helped I've have stuck print after each "if" until the problem became glaringly obvious. BTW, it isn't good to write tests like: if theo == True: "theo" a Boolean anyway. Just say: if theo: It reads more naturally as well. Cheers, Cameron Simpson (formerly c...@zip.com.au) ___ Tutor maillist - Tutor@python.org To unsubscribe or change subscription options: https://mail.python.org/mailman/listinfo/tutor
