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On Jun 6, 8:07*am, "tsangpo" <tsangpo.newsgr...@gmail.com> wrote:
> I want to ensure that the url ends with a '/', now I have to do thisa like
> below.
> url = url + '' if url[-1] == '/' else '/'
>
> Is there a better way?

url+= { '/': '' }.get( url[ -1 ], '/' )

Shorter is always better.

Aaron Brady <> writes:
> url+= { '/': '' }.get( url[ -1 ], '/' )
>
> Shorter is always better.

url = url.rstrip('/') + '/'

On Jun 7, 6:13*pm, Paul Rubin <http://phr...@NOSPAM.invalid> wrote:
> Aaron Brady <castiro...@gmail.com> writes:
> > url+= { '/': '' }.get( url[ -1 ], '/' )
>
> > Shorter is always better.
>
> url = url.rstrip('/') + '/'

I was joking. Sheesh.

Aaron Brady wrote:
> Shorter is always better.
>
> url+= { '/': '' }.get( url[ -1 ], '/' )

Why bother with spaces or 3 letter-wide token, check this ) :
x+={'/':''}.get(x[-1],'/')

Apart from joking, the following proposed solution is by **far** the one
I prefer

> if not url.endswith('/'):
> url += '/'

Maybe not the shorter, but the most concise and clear to me.

Jean-Michel

Jean-Michel Pichavant wrote:
> Aaron Brady wrote:
>> Shorter is always better.
>> url+= { '/': '' }.get( url[ -1 ], '/' )
>
> Why bother with spaces or 3 letter-wide token, check this ) :
> x+={'/':''}.get(x[-1],'/')
>
Even shorter:

x+='/'*(x[-1]!='/')

> Apart from joking, the following proposed solution is by **far** the one
> I prefer
>
>> if not url.endswith('/'):
>> url += '/'
>
> Maybe not the shorter, but the most concise and clear to me.
>
Definitely.

On Jun 8, 9:50*am, Jean-Michel Pichavant <jeanmic...@sequans.com>
wrote:
> Aaron Brady wrote:
> > Shorter is always better.
>
> > url+= { '/': '' }.get( url[ -1 ], '/' )
>
> Why bother with spaces or 3 letter-wide token, check this *) :
> x+={'/':''}.get(x[-1],'/')
>
> Apart from joking, the following proposed solution is by **far** the one
> I prefer
>
> > if not url.endswith('/'):
> > * *url += '/'
>
> Maybe not the shorter, but the most concise and clear to me.

Why won't Python permit:

url.endswith( '/' ) or url.append( '/' )

? Should it? Do we find it just as concise and clear? Does it
outweigh the priority of the immutability of strings? It works on
lists, for example. A sole mutating operation could create a highly
and finely tempered compromise with immutability. Would it be
'append'?

I like Scott's and MRAB's idea for slicing, not indexing, the last
character.

The most literal translation of the original natural language is:

>>> #ensure that the url ends with a '/'
>>> ensure( url, string.endswith, '/' )

(Is it not?) But the parameters aren't sufficient to define 'ensure'
generally, and it won't be able to mutate 'url' regardless.

On Mon, 08 Jun 2009 12:57:58 -0700, Aaron Brady wrote:

> Why won't Python permit:
>
> url.endswith( '/' ) or url.append( '/' )
>
> ?

Because:

(1) Strings are immutable, so that won't work.

(2) Even if it did, you're programming by side-effect, which is bad style
often leading to bugs, and so should be avoided.


> Should it?

Heavens no! It's bad enough that similar expressions are allowed for
lists. Just because they're allowed, doesn't mean we should use them!


> Do we find it just as concise and clear?

No. It *looks* like a boolean expression which is produced then thrown
away uselessly. If not for append() on lists having a side-effect, I'd
call it an expensive no-op.


> Does it
> outweigh the priority of the immutability of strings?

Certainly not. Special cases aren't special enough to break the rules.
Strings have nice consistent behaviour. You're suggesting making their
behaviour inconsistent.



> It works on
> lists, for example. A sole mutating operation could create a highly and
> finely tempered compromise with immutability.

You're not thinking it through. You can't say "strings are immutable,
except for append, which mutates them". If you allow *one* mutable
operation, then the type is mutable, full stop.


> Would it be 'append'?
>
> I like Scott's and MRAB's idea for slicing, not indexing, the last
> character.
>
> The most literal translation of the original natural language is:
>
>>>> #ensure that the url ends with a '/'
>>>> ensure( url, string.endswith, '/' )
>
> (Is it not?) But the parameters aren't sufficient to define 'ensure'
> generally, and it won't be able to mutate 'url' regardless.

This suggestion appears to be a pie-in-the-sky impractical suggestion. It
requires a function ensure() with close to human intelligence to "do what
I mean". As such, I can't take it seriously.


--
Steven

Paul Rubin <http> writes:
> url = url.rstrip('/') + '/'

That's what I use: It has the (nice) side effect of ending the URL with a
*single* slash.

C