eval() in python

[Xah Lee]

is it possible to eval a string like the following?

m='''
i0=[0,1]
i1=[2,3]
i2=[4,'a']

h0=[]
for j0 in i0:
h1=[]
for j1 in i1:
h2=[]
for j2 in i2:
h2.append(f(j0, j1,j2))
h1.append( h2[:] )
h0.append( h1[:] )
return h0'''

perhaps i'm tired, but why can't i run:

t='m=3'
print eval(t)

the doc seems to suggest that eval is only for expressions... it says
uses exec for statements, but i don't seem to see a exec function?

Xah
xah@xahlee.org
∑ http://xahlee.org/

[harold fellermann]

Re: eval() in python

> the doc seems to suggest that eval is only for expressions... it says[color=blue]
> uses exec for statements, but i don't seem to see a exec function?[/color]

Python 2.4 (#1, Dec 30 2004, 08:00:10)
[GCC 3.3 20030304 (Apple Computer, Inc. build 1495)] on darwin
Type "help", "copyright" , "credits" or "license" for more information.[color=blue][color=green][color=darkred]
>>> s="print 'hello Xah Lee :-)'"
>>> exec(s)[/color][/color][/color]
hello Xah Lee :-)[color=blue][color=green][color=darkred]
>>>[/color][/color][/color]

- harold -

--
I wish there was a knob on the TV to turn up the intelligence. There's
a
knob called "brightness ", but it doesn't seem to work.
-- Gallagher

[Peter Hansen]

Re: eval() in python

Xah Lee wrote:[color=blue]
> the doc seems to suggest that eval is only for expressions... it says
> uses exec for statements, but i don't seem to see a exec function?[/color]

Because it's a statement: http://docs.python.org/ref/exec.html#l2h-563

[Jeff Epler]

Re: eval() in python

On Tue, Jun 21, 2005 at 08:13:47AM -0400, Peter Hansen wrote:[color=blue]
> Xah Lee wrote:[color=green]
> > the doc seems to suggest that eval is only for expressions... it says
> > uses exec for statements, but i don't seem to see a exec function?[/color]
>
> Because it's a statement: http://docs.python.org/ref/exec.html#l2h-563[/color]

but the documentation is sooooooo baaaaaaad that it makes babies cry and
maybe spreads herpes too.

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[Benji York]

Re: eval() in python

harold fellermann wrote:[color=blue][color=green][color=darkred]
> >>> s="print 'hello Xah Lee :-)'"
> >>> exec(s)[/color][/color]
> hello Xah Lee :-)[/color]

Note that because "exec" is a statement, the parentheses above are
superfluous.
--
Benji York

[Martin Blume]

Re: eval() in python

"Xah Lee" schrieb[color=blue]
>
> perhaps i'm tired, but why can't i run:
>
> t='m=3'
> print eval(t)
>[/color]
Perhaps you didn't read the documentation? :-)
Perhaps you didn't try hard enough?


C:\WINNT>c:\pro gramme\python\p ython
Python 2.4 (#60, Nov 30 2004, 11:49:19) [MSC v.1310 32 bit (Intel)]
on win32
Type "help", "copyright" , "credits" or "license" for more
information.[color=blue][color=green][color=darkred]
>>> t='m=3'
>>> m[/color][/color][/color]
Traceback (most recent call last):
File "<stdin>", line 1, in ?
NameError: name 'm' is not defined[color=blue][color=green][color=darkred]
>>> exec(t)
>>> m[/color][/color][/color]
3[color=blue][color=green][color=darkred]
>>>[/color][/color][/color]

HTH
Martin