On 14/03/13 02:12, Joshua Wilkerson wrote:
Can you help me with something? This code (it also draws from the text_game
file) says it has a syntax error, but I can't seem to find what it is, I think
the code is having a fit but I'm not sure. I'm appreciative to all hep.
The most valuable help we can give you is to teach you to help yourself, and to
learn what not to do. Here are some Do Nots:
- Do not expect us to read through hundreds of lines of code looking for the
error.
- Do not expect us to save your files and then run them. We have no idea what
they will do, you might be trying to trick us into running harmful code. Unless
we read through all your code and study it carefully, we can't know if it is
safe.
- Even if we trust you AND trust your code, we're volunteers, not servants. We're only
going to install your code and run it if you pay us, or if your problem seems so
interesting that we want to solve the problem no matter how much work it takes.
Unfortunately, "a syntax error" does not sound interesting.
- Don't assume that Python is "having a fit". Trust me, hundreds of thousands
or millions of people have used Python for 20+ years now. No software is perfect and bug
free, but trust me, the chances that you have discovered a bug that nobody before you has
ever seen is remote. 99.99% of the bugs you experience as a programmer will be bugs in
*your* code, not the language. (But don't worry, you'll soon learn to fix those bugs so
quickly you won't even remember them.)
And here are some Dos:
- The most valuable thing you can do right now is learn how to read and
understand the error messages that Python gives you. There is a lot of
information buried in them. And usually not buried very deeply, often all you
need to do is read it and it will tell you what went wrong. (At least once you
get experiences enough to know how to interpret the error.) Compared to some
other languages, Python's error messages are a paragon of clarity and
simplicity.
See below for more on this one.
- If you have trouble with an error that you can't solve yourself, make it easy
for us to help you:
* The absolute LEAST you need to do is copy and paste the entire
traceback, starting with the line "Traceback (most recent call last)"
all the way to the end, including the error message. SyntaxErrors may
not have a Traceback line, but you should still copy and paste the
entire message.
* Better still, if you can, try to SIMPLIFY the problem to the smallest
amount of code that displays the same error. Nine times out of ten, by
going through this process of simplifying the code, *you* will discover
what the error was, and solve the problem yourself. The tenth time, you
will then have a nice, simple piece of code that you can show us,
instead of hundreds and hundreds of lines that we won't read.
See this website for more detail:
http://sscce.org/
Although it is written for Java programmers, the lessons it gives apply
to any language.
* Remember to mention what version of Python you are using, and what
operating system. (Windows, Linux, Mac, something else?) If you are
using a less common Python compiler, like IronPython or Jython, say so.
If you are running your code via an IDE like IDLE or IPython, say so.
Now for this specific error. You are getting a SyntaxError. Unfortunately,
syntax errors sometimes give the least informative error messages in Python.
But fortunately you can still work out what is wrong:
py> for x = range(1, 2):
File "<stdin>", line 1
for x = range(1, 2):
^
SyntaxError: invalid syntax
Notice the small caret ^ on a line on its own? In your email, it may not line up correctly, but if
you read the error in context, in the Python compiler or IDE where it occurs, it will line up with
the first thing that Python found that was broken syntax. In this case, you simply cannot use
assignment, "x = something", inside the for line. The right syntax is "for x in
range(1, 20)".
Here's another example:
py> x = 23*)1+5)
File "<stdin>", line 1
x = 23*)1+5)
^
SyntaxError: invalid syntax
Here the caret should line up under the left-most parenthesis (round bracket).
The solution is to use the open-bracket, not close-bracket.
A common error is to use too few closing brackets.
py> x = 23*(1 + (15 - 7)
... y = x + 1
File "<stdin>", line 2
y = x + 1
^
SyntaxError: invalid syntax
See what happens here? The error, the missing bracket, is on the *previous*
line. That's because Python cannot tell that it is truly missing until it gets
to the next line. So if you have a Syntax Error on a line that looks right, or
that is a comment, *work backwards*, line by line, until you find something
that is missing a closing bracket.
--
Steven
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