percent string replacement with index

[Ulrich Eckhardt]

Hi!

I'm still mostly learning Python and there is one thing that puzzles me
about string formatting. Typical string formatting has these syntaxes:

"%s is %s" % ("GNU", "not Unix")
"%(1)s %(2)s" % ("1":"one", "2":"two")

What I'm surprised is that this isn't supported:

"%(1)s %(2)s" % ("zero", "one", "two")

i.e. specifying the index in a sequence instead of the key into a map (maybe
I would use [1] instead of (1) though). Further, the key can't be a simple
number it seems, which makes this even more inconvenient to me.

Can anyone explain this to me?

Also, why isn't the 's' conversion (i.e. to a string) the default? I
personally would like to just write something like this:

"%1 is not %2" % ("zero", "one", "two")

or maybe

"%[1] is not %[2]" % ("zero", "one", "two")


greetings!

Uli

--
Sator Laser GmbH
Geschäftsführ er: Thorsten Föcking, Amtsgericht Hamburg HR B62 932

[Terry Reedy]

Re: percent string replacement with index



Ulrich Eckhardt wrote:

What I'm surprised is that this isn't supported:
>
"%(1)s %(2)s" % ("zero", "one", "two")
>
i.e. specifying the index in a sequence instead of the key into a map (maybe
I would use [1] instead of (1) though). Further, the key can't be a simple
number it seems, which makes this even more inconvenient to me.
>
Can anyone explain this to me?

History. See below.

>
Also, why isn't the 's' conversion (i.e. to a string) the default? I
personally would like to just write something like this:
>
"%1 is not %2" % ("zero", "one", "two")
>
or maybe
>
"%[1] is not %[2]" % ("zero", "one", "two")

In 2.6 (I believe) and 3.0:

>>"{1} is not {2} or {0}. It is just {1}".format("ze ro", "one", "two")

'one is not two or zero. It is just one'

[Matimus]

Re: percent string replacement with index

On Jun 24, 12:26 pm, Terry Reedy <tjre...@udel.e duwrote:

Ulrich Eckhardt wrote:

What I'm surprised is that this isn't supported:

>

  "%(1)s %(2)s" % ("zero", "one", "two")

>

i.e. specifying the index in a sequence instead of the key into a map (maybe
I would use [1] instead of (1) though). Further, the key can't be a simple
number it seems, which makes this even more inconvenient to me.

>

Can anyone explain this to me?

>
History.  See below.
>
>
>

Also, why isn't the 's' conversion (i.e. to a string) the default? I
personally would like to just write something like this:

>

  "%1 is not %2" % ("zero", "one", "two")

>

or maybe

>

  "%[1] is not %[2]" % ("zero", "one", "two")

>
In 2.6 (I believe) and 3.0:
>
 >>"{1} is not {2} or {0}. It is just {1}".format("ze ro", "one", "two")

Or even:

>>"{0[1]} is not {0[2]} or {0[0]}. It is just {0[1]}".format(["zero", "one", "two"])

'one is not two or zero. It is just one'

Or

>>"{one} is not {two} or {zero}. It is just {one}".format(z ero="zero", one="one", two="two")

'one is not two or zero. It is just one'

Or

>>class C(object):

... def __init__(self, zero, one, two):
... self.zero = zero
... self.one = one
... self.two = two
...

>>"{0.one} is not {0.two} or {0.zero}. It is just {0.one}".format (C("zero", "one", "two"))

'one is not two or zero. It is just one'

More information: http://www.python.org/dev/peps/pep-3101/

Exciting stuff.

Matt

[Ulrich Eckhardt]

Re: percent string replacement with index

Ulrich Eckhardt wrote:

What I'm surprised is that this isn't supported:
>
"%(1)s %(2)s" % ("zero", "one", "two")

Thanks Terry and Matimus, actually I'm using 2.4 and considering upgrading
now. ;)

Uli

--
Sator Laser GmbH
Geschäftsführ er: Thorsten Föcking, Amtsgericht Hamburg HR B62 932