Question

On week 2 beginning 'Iteration', I get an error on the print statement see below
http://pastebin.com/raw.php?i=sFhLznUw

Any one know why ?

Answer 1

i don't get an error
what did the traceback say?

Answer 2

@minimallinux
check your spelling.
Python is case sensitive:P

Answer 3

File "<stdin>", line 4
print (str(x) + '*' + str(x) + '=' + str(ans))
^
SyntaxError: invalid syntax
>>>

Answer 4

itersleft = itersLeft - 1 << wrong spelling

Answer 5

Fixed that still error

x = 3
>>> ans = 0
>>> itersLeft = x
>>> while (itersLeft != 0):
... ans = ans + x
... itersLeft = itersLeft - 1
... print (str(x) + '*' + str(x) + '=' + str(ans))
File "<stdin>", line 4
print (str(x) + '*' + str(x) + '=' + str(ans))

Answer 6

print (str(x) + '*' + str(x) + '=' + str(ans)) >>>>>
print(str(x) + '*' + str(x) + '=' + str(ans)) might be this too (the space betweent print and parenthesis)

Answer 7

between*

Answer 8

Does't seem to be a problem on other print statements, seem to get error whichever way I try it, even copy paste original code !

Answer 9

ie. the file I download produces error

Answer 10

hmm let me see again

Answer 11

i just saw ...are u doing it in IDLE or on a new file? i mean for me even without touching the print statement it runs properly.

Answer 12

>>> while (itersLeft != 0):
... ans = ans + x
... itersLeft = itersLeft - 1
... print (str(x) + '*' + str(x) + '=' + str(ans))


thats too much for IDLE i think...i believe u are supposed to write that long code into the other python window and then run the whole from there.
i wrote the code in the IDLE and it gives me the same error it gives u.BUT, if i write it into the code window(or help me here how it is called) it works fine.

Answer 13

No I don't use idle just standard python shell

Answer 14

ok w8 i confused the python windows names.
i wanted to say that ,when i used the shell it gave me error....but if u use [File>>>New Window] and write it there it runs normally.

Answer 15

I've got 2.6 and 3.3 and both show error

Answer 16

did u do it like i told u?
on shell window go file>>>New Window
then write ur code there and press f5 (to run it).

Answer 17

Ill try

Answer 18

same in idle, error in syntax even with the original file

Answer 19

Getting a little baffling

Answer 20

hmm dont know how to help u :( works fine for me...could u pass some screens maybe somehow?

Answer 21

Yes I will attach a screenshot if possible

Answer 22

Using what I see here, if I duplicate it I can get the same error in the python shell unless I hit <enter> again before the print so the ... changes to >>> Can't duplicate error in idle.

x = 3
>>> ans = 0
>>> itersLeft = x
>>> while (itersLeft != 0):
... ans = ans + x
... itersLeft = itersLeft - 1
... print (str(x) + '*' + str(x) + '=' + str(ans))
File "<stdin>", line 4
print (str(x) + '*' + str(x) + '=' + str(ans))

Answer 23

So I have attached iterate.jpg, a screenshot of my python shell running the code to an error

Answer 24

minima btw do u use the suggested version of python? i mean might that be the problem?
http://www.enthought.com/products/epd_free.php

Answer 25

I have both 2.6 and 3.3

Answer 26

I prefer just the shell, it should work

Answer 27

suggested is 2.7 and in the screen u r using shell (i think) not the window i told u to try.

Answer 28

As above I can duplicate what your image shows but hitting <enter> again like I said makes it work

Answer 29

Yes just the shell but it SHOULD work

Answer 30

OK Ill hit twice

Answer 31

xD tell us what happens when u hot twice:P

Answer 32

No I get the error even then

Answer 33

It must be something simple

Answer 34

when i paste thsi into shell:
x = 3
ans = 0
itersLeft = x
while (itersLeft != 0):
ans = ans + x
itersLeft = itersLeft - 1
print(str(x) + '*' + str(x) + '=' + str(ans))
i get no error...but i dont get any answer either:P
thats crazy xD

Answer 35

if i try to write command per command it gives me the error

Answer 36

good idea:)

Answer 37

@msmithhnova ok i now got what u meant by enter twice
yes it works for me aswell now.

Answer 38

no i believe u just didnt do what msmith says.
before u write the print statment enter wtice so u ge the >>>
then write the print statement.

Answer 39

Yeah the way I look at that is since you didn't hit enter again to exit the while loop code it thinks it is still in the while loop but then it gets to the print which is not indented and realizes it isn't. So now it goes "ok i am in the loop but i'm not in the loop, huh" , throws it's virtual hands up in the air and says "I give up" (syntax error)

Answer 40

hahhahah poor code!!!

Answer 41

... yes, you need to enter the print statement at a shell prompt
you haven't let the interpreter execute the while statement/suite and it doesn't like that at all. the shell lets you enter multiline compound statements but if you try to include something 'outside' of the compund statement it will complain http://dpaste.com/810233/

Answer 42

did you see my code paste?

Answer 43

the problem is definitely an indentation problem.

you have entered a multiline compound statement into the shell

the print statement has been entered before the shell can process the compound statement BUT the print statement indentation places it outside of the compound statements execution suite

the shell doesn't like this so it complains.

try typing all that into a text file and running the file/module/script from the shell - do linux files need an extension (.py)?

Answer 44

Sorry folks, it is not suspect i just got it working by running it as a file in normal shell (the equivalent of running in idle) as opposed to typing into a python shell here is my result

[anton@Centos ~]$ python iterstest.py
3*3 = 9

So sorry for the accusations, recriminations and the loss of around 3 hours !

Answer 45

bwCA is right

Answer 46

I can put 3.3 back on now

Answer 47

yeay - i don't bother much with the command prompt shell so i had to try it for myself

Answer 48

I'm not keen on the idle so I will run them as file in shell

Answer 49

So we have to be careful of typing into shell with multiline statements

Answer 50

yep
the shell only executes one 'statement' at a time.

it recognizes compound statements and allows you to enter the multiple lines

it (apparently) recognizes that you are done with the compound statement when you enter a blank line - then executes it

if you mess up and enter two separate statements it identifies it as a syntax error

don't stop using the shell tho, it is a great way to try things out and see if they work. now you know about compound statements in the shell so keep using it. when you are writing a program in a file and having trouble with it, the shell is a great place to try bits and pieces of it to narrow down the problem - often you can write simplified versions of your code in the shell to test out structure or logic and it is very convenient

Answer 51

And my equivalent of idle is to put it in a .py file and run it with the python command