Dynamic Zero Padding.

[Friedrich Clausen]

Hello All,

I want to print some integers in a zero padded fashion, eg. :

>>> print("Testing %04i" % 1)
Testing 0001

but the padding needs to be dynamic eg. sometimes %05i, %02i or some
other padding amount. But I can't insert a variable into the format
specification to achieve the desirable padding.

I would be much obliged if someone can give me some tips on how to
achieve a variably pad a number.

Cheers,

Fred.

Thanks,

Fred.

[Mel]

:)

('%%0%dd' % (pads,)) % (n,)

Probably be good to wrap it in a function. It looks kind of obscure as it
is.

Mel.

[Chris Rebert]

On Tue, Jun 7, 2011 at 2:36 PM, Friedrich Clausen <fr...@derf.nl> wrote:
> Hello All,

>
> I want to print some integers in a zero padded fashion, eg. :
>
>>>> print("Testing %04i" % 1)
> Testing 0001
>
> but the padding needs to be dynamic eg. sometimes %05i, %02i or some
> other padding amount. But I can't insert a variable into the format
> specification to achieve the desirable padding.
>
> I would be much obliged if someone can give me some tips on how to
> achieve a variably pad a number.

http://docs.python.org/library/stdtypes.html#str.zfill

Cheers,
Chris

[Emile van Sebille]

On 6/7/2011 2:36 PM Friedrich Clausen said...

> Hello All,
>
> I want to print some integers in a zero padded fashion, eg. :
>
>>>> print("Testing %04i" % 1)
> Testing 0001
>
> but the padding needs to be dynamic eg. sometimes %05i, %02i or some
> other padding amount. But I can't insert a variable into the format
> specification to achieve the desirable padding.
>
> I would be much obliged if someone can give me some tips on how to
> achieve a variably pad a number.

Something like this works:

>>> for ii in ((3,12),(4,140),(5,123)):
... print ("Testing %%%02ii" % ii[0]) % ii[1]
...
Testing 012
Testing 0140
Testing 00123

Emile

[Ethan Furman]

Friedrich Clausen wrote:
> Hello All,
>
> I want to print some integers in a zero padded fashion, eg. :
>
>>>> print("Testing %04i" % 1)
> Testing 0001
>
> but the padding needs to be dynamic eg. sometimes %05i, %02i or some
> other padding amount. But I can't insert a variable into the format
> specification to achieve the desirable padding.
>
> I would be much obliged if someone can give me some tips on how to
> achieve a variably pad a number.

--> width = 3
--> print("Testing %0*i" % (width, 1))
Testing 001
--> width = 7
--> print("Testing %0*i" % (width, 1))
Testing 0000001

The '*' acts as a place holder for the width argument.

~Ethan~

[harrismh777]

Friedrich Clausen wrote:
> I would be much obliged if someone can give me some tips on how to
> achieve a variably pad a number.

>>>> b='04'
>>>> a="testing %"+b+"i"
>>>> print(a % 1)
> testing 0001

kind regards,
m harris

[Prasad, Ramit]

Python 2.6.x
>>> 'test {0:.2f}'.format(1)
'test 1.00'
>>> 'test {0:{1}f}'.format(1,2)
'test 1.000000'
>>> 'test {0:{1}f}'.format(1,.2)
'test 1.00'
>>> 'test {0:.{1}f}'.format(1,2)
'test 1.00'


Ramit


Ramit Prasad | JPMorgan Chase Investment Bank | Currencies Technology
712 Main Street | Houston, TX 77002
work phone: 713 - 216 - 5423

-----Original Message-----
From: python-list-bounces+ramit.prasad=jpmcha...@python.org [mailto:python-list-bounces+ramit.prasad=jpmcha...@python.org] On Behalf Of Friedrich Clausen
Sent: Tuesday, June 07, 2011 4:37 PM
To: pytho...@python.org
Subject: Dynamic Zero Padding.

Hello All,

I want to print some integers in a zero padded fashion, eg. :

>>> print("Testing %04i" % 1)
Testing 0001

but the padding needs to be dynamic eg. sometimes %05i, %02i or some
other padding amount. But I can't insert a variable into the format
specification to achieve the desirable padding.

I would be much obliged if someone can give me some tips on how to
achieve a variably pad a number.

Cheers,

Fred.

Thanks,

Fred.
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[harrismh777]

Ethan Furman wrote:
> --> print("Testing %0*i" % (width, 1))

> The '*' acts as a place holder for the width argument.

very nice...

[MRAB]

On 07/06/2011 22:36, Friedrich Clausen wrote:
> Hello All,
>
> I want to print some integers in a zero padded fashion, eg. :
>
>>>> print("Testing %04i" % 1)
> Testing 0001
>
> but the padding needs to be dynamic eg. sometimes %05i, %02i or some
> other padding amount. But I can't insert a variable into the format
> specification to achieve the desirable padding.
>
> I would be much obliged if someone can give me some tips on how to
> achieve a variably pad a number.
>

>>> "Testing %0*i" % (4, 1)
'Testing 0001'
>>> "Testing %0*i" % (5, 1)
'Testing 00001'

[Chris Angelico]

On Wed, Jun 8, 2011 at 7:43 AM, Mel <mwi...@the-wire.com> wrote:
> :)
>
> ('%%0%dd' % (pads,)) % (n,)
>
> Probably be good to wrap it in a function.  It looks kind of obscure as it
> is.

Would get rather pretty (read: ugly and impossible to read) if you
wanted to put a literal percent sign in front of the number.

:)

Chris Angelico

[Larry Hudson]

It works for precision as well as width.

wid = 10
prec = 3
num = 123.456789
print "%0*.*f" % (wid, prec, num)

gives you -> 000123.457

(It's the same as the printf() function in C.)

-=- Larry -=-

[Terry Reedy]

On 6/7/2011 7:05 PM, John Posner wrote:

> You might want to try "new style" string formatting [1], which I think
> is better than the "old style" in this particular case:
>
> >>> "Testing {0:0{1}d}".format(42, 4)
> 'Testing 0042'
> >>> "Testing {0:0{1}d}".format(42, 9)
> 'Testing 000000042'

One cannot use a nested field in the 'name' part of the field (before
the ':' (I tried), but are pretty free to nest in the actual
specification part after the ':'.

>>> '{0:{1}}'.format(7,'b')
'111'
>>> '{0:{1}}'.format(7,'d')
'7'

--
Terry Jan Reedy

[Friedrich Clausen]

Thanks all for the many good suggestions - I am looking over them and
reading the referenced docs.

Cheers,

Fred.