TypeError: unsubscriptable object.

[Balaji]

Hello Everybody...

I have a problem..

This is the code...
--------------------------------------
class Stack:

def __init__(self,e xpr):
self.stackP=[]
self.stackF=1
self.a = {}
# self.stackManag ement(expr)
if not self.a.has_key( 'rhs'):
self.a['rhs'] = 0
# self.a['rhs'] += self.popP()*sel f.popF()

def pushP(self,obj) :
self.stackP.app end(obj)

def pushF(self,obj) :
stackF=stackF*o bj
return stackF

def popP(self):
rval=0
rval=self.stack P.pop()
return rval

def popF(self,obj):
stackF/=obj
return stackF

def peekP(self):
rval=0
rval= self.stackP[-1]
return rval
def peekF(self):
rval=0
rval= self.stackF[-1]
return rval
def stackManagement (self,expr):

#Determine the next symbol
if expr.__class__= =E:
self.pushP(expr .operator)
self.stackManag ement(expr.left )
self.stackManag ement(expr.righ t)
else:
self.pushP(expr )
if len(self.stackP ) > 1:
s = self.peekP()
prev = self.stackP[-2]
if prev in ('*','+','/','-'):
if prev in ('*','/'):
self.pushF(self .peekF()*s)
else:#stackP[-3] must be an operator.
top=self.popP()
mid =self.popP()
op=self.popP()
if op == '*':
if top.__class__== V:
self.a += self.popF(self. stackF)

self.stackManag ement(0)
else:
self.popF(self. stackF)
self.stackManag ement(mid*top)
if op == '+':
if top.__class__== V:
self.a+= self.peekF()

self.stackManag ement(0)
else:
self.stackManag ement(mid+top)
if op == '-':
if top.__class__== V:
self.a -= self.peekF()

self.stackManag ement(0)
else:
self.stackManag ement(mid-top)
if op == '/':
if top.__class__== V:
self.a /= self.popF(self. stackF)/(mid**2)

self.stackManag ement(0)
else:
self.popF(self. stackF)
self.stackManag ement(top/mid)
else:
self.a['rhs'] += self.popP(self. stackP)*self.po pF(self.stackF)

and I'm giveing the following calls...
---------------------------

from expression import *
from generation import*

(x,y,z) = (V(),V(),V()) # making instances of Variable class

e1=x+y+z

s=Stack(e1)

s.stackManageme nt(e1)
----------------------------------------------
I'm getting the following error TypeError: unsubscriptable object...
Traceback (most recent call last):
File "<stdin>", line 1, in ?
File "generation.py" , line 175, in stackManagement
self.stackManag ement(expr.left )
File "generation.py" , line 176, in stackManagement
self.stackManag ement(expr.righ t)
File "generation.py" , line 199, in stackManagement
self.a+= self.peekF()
File "generation.py" , line 168, in peekF
rval= self.stackF[-1]
-------------------------------------
I 'm at my wit ends..

Can anyone help...

Thx in advance

[Terry Reedy]

Re: TypeError: unsubscriptable object.


"Balaji" <balaji@email.a rizona.edu> wrote in message
news:494182a9.0 405211340.49873 a72@posting.goo gle.com...[color=blue]
> class Stack:
>
> def __init__(self,e xpr):[/color]

Note: tabs get eaten by some newsreaders.
[color=blue]
> self.stackP=[]
> self.stackF=1[/color]
....[color=blue]
> def peekF(self):
> rval = 0 # useless line
> rval= self.stackF[-1]
> return rval[/color]
# return self.stackF[-1] would be easier to read

See the potential problem? (If not, add
'print type(self.stack F)' to the top of this function.)
[color=blue]
> def stackManagement (self,expr):[/color]
....[color=blue]
> self.a+= self.peekF()[/color]

which now seems quite possible.
....[color=blue]
> s.stackManageme nt(e1)
> ----------------------------------------------
> I'm getting the following error TypeError: unsubscriptable object...[/color]

which means you tried to subscript an unsubscriptable object
[color=blue]
> Traceback (most recent call last):
> File "<stdin>", line 1, in ?
> File "generation.py" , line 175, in stackManagement
> self.stackManag ement(expr.left )
> File "generation.py" , line 176, in stackManagement
> self.stackManag ement(expr.righ t)
> File "generation.py" , line 199, in stackManagement
> self.a+= self.peekF()
> File "generation.py" , line 168, in peekF
> rval= self.stackF[-1][/color]

in the line immediately above.

Terry J. Reedy

[Mel Wilson]

Re: TypeError: unsubscriptable object.

In article <494182a9.04052 11340.49873a72@ posting.google. com>,
balaji@email.ar izona.edu (Balaji) wrote:[color=blue]
>Hello Everybody...
>
>I have a problem..[/color]
[ ... ][color=blue]
>----------------------------------------------
>I'm getting the following error TypeError: unsubscriptable object...
>Traceback (most recent call last):
> File "<stdin>", line 1, in ?
> File "generation.py" , line 175, in stackManagement
> self.stackManag ement(expr.left )
> File "generation.py" , line 176, in stackManagement
> self.stackManag ement(expr.righ t)
> File "generation.py" , line 199, in stackManagement
> self.a+= self.peekF()
> File "generation.py" , line 168, in peekF
> rval= self.stackF[-1]
>-------------------------------------
>I 'm at my wit ends..
>
>Can anyone help...[/color]

Something has come unstuck. I would try wrapping
the failing statement:

try:
rval= self.stackF[-1]
except TypeError:
print "TypeError, self.stackF:", repr(self.stack F)
sys.exit (-1)

and see what comes out.

Regards. Mel.