Do I need to convert string to integer in python?

[Allerdyce.John@gmail.com]

Do I need to convert string to integer in python? or it will do it for
me (since dynamic type)?

In my python script, I have this line:
x /= 10;

when i run it, I get this error:
TypeError: unsupported operand type(s) for /=: 'unicode' and 'int'

I want to divide x by 10 and assign that value back to x.

Thank you.

[Heiko Wundram]

Re: Do I need to convert string to integer in python?

Allerdyce.John@ gmail.com wrote:[color=blue]
> Do I need to convert string to integer in python? or it will do it for
> me (since dynamic type)?[/color]

Yes. Dynamic typing doesn't say anything about a string and a number being
"equal," as they are (e.g.) in Perl, it just says that you don't have to
care what type of object a name is bound to. What you are thinking of is
called weak typing (auto-coercion between strings and numbers and such).

You'd have to do something like:
x = int(x)/10

--- Heiko.

[Alex Martelli]

Re: Do I need to convert string to integer in python?

<Allerdyce.John @gmail.com> wrote:
[color=blue]
> Do I need to convert string to integer in python? or it will do it for
> me (since dynamic type)?[/color]

Nope, no such implicit conversion (thanks be!). Strings are strings and
ints and ints and never the twain shall meet, except by explicit
request;-).

[color=blue]
> In my python script, I have this line:
> x /= 10;
>
> when i run it, I get this error:
> TypeError: unsupported operand type(s) for /=: 'unicode' and 'int'
>
> I want to divide x by 10 and assign that value back to x.[/color]

If you want x to remain a Unicode string when you're done,

x = unicode(int(x) / 10)

should work. If you want x to become an integer, omit the unicode call
around the int(x)/10 expression.


Alex

[Diez B. Roggisch]

Re: Do I need to convert string to integer in python?

Allerdyce.John@ gmail.com schrieb:[color=blue]
> Do I need to convert string to integer in python? or it will do it for
> me (since dynamic type)?
>
> In my python script, I have this line:
> x /= 10;
>
> when i run it, I get this error:
> TypeError: unsupported operand type(s) for /=: 'unicode' and 'int'
>
> I want to divide x by 10 and assign that value back to x.[/color]

Yes, you have to convert beforehand. Dynamic typing and weak typing (as in perl or php) aren't the same thing.

Dynamic typing means that you can rebind a variable (or better name) at runtime to contain a value with a new type. Weak
typing means that an object is reinterpreted as a value of another type when needed - and (often) leads to difficult errors.


Regards,

Diez

[Michael Amrhein]

Re: Do I need to convert string to integer in python?

Allerdyce.John@ gmail.com schrieb:[color=blue]
> Do I need to convert string to integer in python? or it will do it for
> me (since dynamic type)?
>
> In my python script, I have this line:
> x /= 10;
>
> when i run it, I get this error:
> TypeError: unsupported operand type(s) for /=: 'unicode' and 'int'
>
> I want to divide x by 10 and assign that value back to x.
>
> Thank you.
>[color=green][color=darkred]
>>> x=100
>>> x/=10
>>> x[/color][/color][/color]
10[color=blue][color=green][color=darkred]
>>> x='100'
>>> x/=10[/color][/color][/color]

Traceback (most recent call last):
File "<pyshell#4 >", line 1, in -toplevel-
x/=10
TypeError: unsupported operand type(s) for /=: 'str' and 'int'[color=blue][color=green][color=darkred]
>>> x=int(x)/10
>>> x[/color][/color][/color]
10

Michael

[Steven D'Aprano]

Re: Do I need to convert string to integer in python?

On Sun, 26 Feb 2006 11:55:54 -0800, Allerdyce.John wrote:
[color=blue]
> Do I need to convert string to integer in python? or it will do it for
> me (since dynamic type)?
>
> In my python script, I have this line:
> x /= 10;
>
> when i run it, I get this error:
> TypeError: unsupported operand type(s) for /=: 'unicode' and 'int'[/color]

No, the Python interpreter is playing a practical joke on you when it
raises that exception. Just persevere with the x /= 10 line, and
eventually the interpreter will give in and give you the result you need.
But be warned, if it is in a particularly playful mood, you may need to
try hundreds of times before it will stop messing about and get back to
work.

By the way, semi-colons are not required at the end of lines in Python.


--
Steven.