Python and Tkinter: Function madness

Question

I'm trying to write myself a program that calculates a function taken from a Tk.Entry().
The problem is, when I try to run my display() function
(it runs Tkinter, sets up the window, and calls root.Mainloop()),
I get parse errors coming from eval() from a function that is supposed to be called only if the user inputs all of the variables and presses a button (the button's command).
The function uses eval(variable), while variable is entry.get().
What am I doing wrong here?

def cfunc(_n,_f,_t0,_tn,):  
 xbase=[]  
 tbase=[]  
 t=0      
 n2=eval(_n)  #Stuff happens here, cfunc gets entry_n.get() as arguments.  
 f2=_f  #Also, tabs are correct in the original.  
 tmin2=eval(_t0)  
 tmax2=eval(_tn)  
 tr=tmax2-tmin2  
 sk = tr / n2  
 i2=tmin2

Also, error:

File "Q:\Py\counter.py", line 89, in
cfunc n2=eval(_n) File "", line 0
^ SyntaxError: unexpected EOF while parsing

Could you please post the error and possibly part of the code that causes the errors? — Utku Zihnioglu
Hard to say without seeing any code. From the symptoms I'd say you're evaluating something too early instead of wrapping it e.g. in a lambda — 6502
We can't know what exactly causes this, but no matter whether eval plays a part in it or not: Using eval is the real madness ;) — user395760

Bryan Oakley Bryan Oakley · Accepted Answer · 2011-02-14T11:49:49

You haven't shown us the code that causes the error (the value of _n) so we can only guess. A couple words of advice:

the error message is telling you the problem: unexpected eof. That means there's a missing closing quote or brace or something like that. The parser got to the end of the "file" (the string being eval'd) before it got the characters it expected.
put a print statement immediately before an eval, and use some special characters to delimit it (eg: puts ">>>$_n<<<") so you can tell precisely what is in the string being eval'd, including any leading or trailing spaces.

Python and Tkinter: Function madness

1 Answers