newbie str to int

[Gerhard Häring]

On Tue, Oct 02, 2001 at 12:22:29PM +0800, James wrote:
> I am switching from Perl to Python, and would
> like to convert string '123abc' to integer 123.

123abc is no valid decimal number.

> foo = int('123abc') # error
> foo = string.atoi('123abc') #error
> foo = eval('123abc') # error

I'd expect this from a programming language.

> I tried the above, then tried the following.
> 
> tmp = ''
> for i in '123abc':
>     if 47 < ord(i) < 58:
>         tmp += i
> foo = int(tmp) # yay
> 
> Why doing simple thing like this is so complicated ?

Because it's quite an artificial example? I've never needed anything
like this. Ignoring errors in input is not a good thing IMHO. In an
application, I'd alert the user that what he typed in is not a number
and that he, please, provide a valid number.

> Perl
> $foo = '123abc' + 0;

Why doesn't Perl convert this to 1194684? Isn't it smart enough to see
that 123abc is a hex number? ;-)

In one sentence: Python doesn't guess. And that's good.

Gerhard
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reduce(lambda x,y:x+y,map(lambda x:chr(ord(x)^42),tuple('zS^BED\nX_FOY\x0b')))