[Tutor] Generating random in a user specified range.

[Adam]

Magnus Lycka wrote:

> Adam wrote:
> 
>>However, I seem to have a problem - I get an error using 
>>random.randint(a,b) and with random.randrange(a,b). 
> 
> 
> It's *much* easier to help you if you tell us exactly the error 
> messages you get. Can't you copy the traceback directly to the mail?
> 
> Btw, used with two integers as arguments, random.randint(x,y) is
> exactly the same thing as random.randrange(x,y+1). You can expect
> them to behave fairly similarly from an error point of view, but
> note that your "top" value will never be returned from 
> randrange(bottom, top). See below:
> 
> 
>>>>import random
>>>>random.randint(1,1)
> 
> 1
> 
>>>>random.randrange(1,2)
> 
> 1
> 
>>>>random.randrange(1,1)
> 
> 
> Traceback (most recent call last):
>   File "<pyshell#40>", line 1, in -toplevel-
>     random.randrange(1,1)
>   File "D:\Python23\lib\random.py", line 171, in randrange
>     raise ValueError, "empty range for randrange()"
> ValueError: empty range for randrange()
> 
> 
>>It seems that it 
>>might be fussy accepting parts of a list as the argument. I've tried 
> 
> 
> If "x = [5, 20]", then x[0] and x[1] are integers, not "parts of a list",
> so this isn't your problem.
> 
> 
>>>>x = [5, 20]
>>>>random.randint(x[0], x[1])
> 
> 15
> 
>>>>random.randrange(x[0], x[1])
> 
> 14
> 
> No problems!
> 
> 
>>converting them to integers and then passing the interger, but it still 
>>complains.
> 
> 
> You *should* provide integers as parameters with random.randrange().
> Never strings. 
> 
> Python is not a toy language that tries to guess what the programmer 
> meant and corrects him silently when he made a mistake. In the long 
> run, the Python tenet: "In the face of ambiguity, refuse the temptation 
> to guess" is very helpful when we try to build robust applications.
> 
> 
>>range = range() 
> 
> 
> I assume you have this *after* your function definition in your actual
> program, otherwise it will not call your not yet defined function, but
> rather to the standard built in Python function called range. E.g.
> 
> Traceback (most recent call last):
>   File "C:/TEMP/temp.py", line 1, in -toplevel-
>     range = range()
> TypeError: range expected at least 1 arguments, got 0
> 
> 
>>def range():
> 
> 
> As I said, range is the name of a builtin function. It's not a good idea 
> to hide builtin functions with user defined ones.
> 
> If I take your code, add "import random" at the top, and move the
> initial lines to the end of the program, after the functions, it works
> as expected, with no errors. (Well, I guess you actually want randint
> rather than randrange as explained above.)
> 

Just a quick thanks to everyone who replied - I got this working.

Adam