error with string (beginner)

[Alex Pavluck]

Hello. I get the following error with the following code. Is there
something wrong with my Python installation?

code:
import types
something = input("Enter something and I will tell you the type: ")

if type(something) is types.IntType:
print "you entered an integer"
elif type(something) is types.StringTyp e:
print "you entered a string"

error:
String: Source for exec/eval is unavailable

[K.S.Sreeram]

Re: error with string (beginner)

Alex Pavluck wrote:[color=blue]
> String: Source for exec/eval is unavailable[/color]

I'm not able to find this message anywhere in the Python-2.4.3 sources.
What python version are you using? What input did you enter when the
prompt appeared? and copy&paste the *exact* exception you got including
the full traceback.

Regards
Sreeram


-----BEGIN PGP SIGNATURE-----
Version: GnuPG v1.4.2.2 (MingW32)
Comment: Using GnuPG with Mozilla - http://enigmail.mozdev.org

iD8DBQFEnpwXrgn 0plK5qqURAk7fAJ 9I449qtRT8HbpHF ScM6RcbTGL8HwCe P9+G
YM8xbP7i0cyS1Dy a56nAv4c=
=X7Ek
-----END PGP SIGNATURE-----

[Jon Clements]

Re: error with string (beginner)


Alex Pavluck wrote:[color=blue]
> Hello. I get the following error with the following code. Is there
> something wrong with my Python installation?
>
> code:
> import types
> something = input("Enter something and I will tell you the type: ")
>
> if type(something) is types.IntType:
> print "you entered an integer"
> elif type(something) is types.StringTyp e:
> print "you entered a string"
>
> error:
> String: Source for exec/eval is unavailable[/color]
[color=blue]
>From the docs:[/color]
"""
input( [prompt])

Equivalent to eval(raw_input( prompt)). Warning: This function is not
safe from user errors! It expects a valid Python expression as input;
if the input is not syntactically valid, a SyntaxError will be raised.
Other exceptions may be raised if there is an error during evaluation.
(On the other hand, sometimes this is exactly what you need when
writing a quick script for expert use.)
If the readline module was loaded, then input() will use it to provide
elaborate line editing and history features.

Consider using the raw_input() function for general input from users.
""""

So you want be using raw_input() for starters...

Cheers,

Jon.

[Jason]

Re: error with string (beginner)

I believe what you are trying to do is something like the following.

def isIntLike(x):
try:    int(x)
except: return False
else:   return True

something = raw_input("Enter something and I will tell you the type: ")

if isIntLike(something):	print "I am an int"
elif isinstance(something, type('')):	print "I am a string"
else:	print "I am an impostor!"

Note that you should be using raw_input() rather than input(). The
former always returns a string. The latter tries to execute the input,
hence your error message.

Also note that everything input on the command line is a string,
regardless of what you type. If you want type checking, use C++ or
java. If you want to check for anything more than IntLike strings, you
should consider using regular expressions through the 're' package.
For user-defined types, use 'isinstance(som ething, class object)' to
check for a type.

Lastly, you may be interested in the 'getopt' module, which handles
command line arguments (as opposed to prompting user for input)
automatically. See here:

http://python.active-venture.com/lib/module-getopt.html

Check out the Python Cookbook for lots of good examples:

http://aspn.activestate.com/ASPN/Cookbook/Python

HTH,

Jay



Alex Pavluck wrote:[color=blue]
> Hello. I get the following error with the following code. Is there
> something wrong with my Python installation?
>
> code:
> import types
> something = input("Enter something and I will tell you the type: ")
>
> if type(something) is types.IntType:
> print "you entered an integer"
> elif type(something) is types.StringTyp e:
> print "you entered a string"
>
> error:
> String: Source for exec/eval is unavailable[/color]

[Cameron Laird]

Re: error with string (beginner)

In article <1151240297.725 336.305960@i40g 2000cwc.googleg roups.com>,
Alex Pavluck <apavluck@gmail .com> wrote:[color=blue]
>Hello. I get the following error with the following code. Is there
>something wrong with my Python installation?
>
>code:
>import types
>something = input("Enter something and I will tell you the type: ")
>
>if type(something) is types.IntType:
> print "you entered an integer"
>elif type(something) is types.StringTyp e:
> print "you entered a string"
>
>error:
>String: Source for exec/eval is unavailable
>[/color]

There are several things wrong--'least three distinct ones, by my count.

What version of Python do you believe you're using? What input do you
enter at the "Enter something ..." prompt?

I suspect you're going to have happier results all around when you
replace "input" with "raw_input" . I encourage you to read the documenta-
tion for each.

[Bruno Desthuilliers]

Re: error with string (beginner)

Jason wrote:[color=blue]
> I believe what you are trying to do is something like the following.
>
>

> def isIntLike(x):
> 	try:    int(x)
> 	except: return False[/color]

*Never* ever use a bare except clause. *Always* specify wich exceptions
you are expecting. (NB : here, TypeError and ValueError).

(NB :  of course, like for all and any do's-and-don't rules, there are
actually a very few cases where using a bare except may be ok.)
[color=blue]
> 	else:   return True
>
> something = raw_input("Enter something and I will tell you the type: ")
>
> if isIntLike(something):	print "I am an int"[/color]

Nope. At this stage, 'something' is *not* an int - it's a string that
can be turned into an int.
[color=blue]
> elif isinstance(something, type('')):	print "I am a string"[/color]

You don't need the "type('')" stuff - use isinstance(something,
basestring) instead.
[color=blue]
> else:	print "I am an impostor!"
>

[/color]

(snip)

--
bruno desthuilliers
python -c "print '@'.join(['.'.join([w[::-1] for w in p.split('.')]) for
p in 'onurb@xiludom. gro'.split('@')])"