Re: PEP 378: Format Specifier for Thousands Separator
On May 23, 2:42 pm, Dave Angel da...@davea.name wrote:
On 05/23/2013 11:26 AM, Carlos Nepomuceno wrote:
Date: Thu, 23 May 2013 06:44:05 -0700
Subject: Re: PEP 378: Format Specifier for Thousands Separator
From: prueba...@latinmail.com
To: python-l...@python.org
[...]
You left out the part where a and f are initialized:
a='%s'
f=(3,5)
eggs(a,f)
Traceback (most recent call last):
File pyshell#29, line 1, in module
eggs(a,f)
File pyshell#1, line 1, in eggs
def eggs(spam, ham): return spam % ham
TypeError: not all arguments converted during string formatting
'%s'%(5%3)
'2'
So % doesn't handle tuples! Why's that? Is it intentional (by design)?
It's a conflict in the design. A tuple is used to supply multiple
arguments to the % operator. So if you want to have a tuple as the
first argument, you need to enclose it in another tuple.
try the following:
print a % (f,)
The trouble is, it doesn't generalize very readily, so it's difficult to
use in a function like eggs()
--
DaveA
It's all there, it's just that quoting ate it. Let's try this again:
def eggs(spam, ham): return spam % ham
def milk(beef, steak): return beef.format(steak)
a='%s'
c=9
d=4
e=[1,2]
f=(3,5)
d='{}'
eggs(a,4)
'4'
eggs(c,4)
1
eggs(a,e)
'[1, 2]'
eggs(a,f)
Traceback (most recent call last):
File pyshell#29, line 1, in module
eggs(a,f)
File pyshell#1, line 1, in eggs
def eggs(spam, ham): return spam % ham
TypeError: not all arguments converted during string formatting
'%s'%(5%3)
'2'
milk(d,4)
'4'
milk(c,4)
Traceback (most recent call last):
File pyshell#53, line 1, in module
milk(c,4)
File pyshell#49, line 1, in milk
def milk(beef, steak): return beef.format(steak)
AttributeError: 'int' object has no attribute 'format'
milk(d,e)
'[1, 2]'
milk(d,f)
'(3, 5)'
'{}'.format(5%3)
'2'
The three issues represented:
1. Functions in which both values of the operator are parameters might
not return a string but an integer instead. It is not always
immediately obvious when reading such functions if modulus or
formatting is intended.
2. Function doesn't handle tuple properly unless carefully written
3. Too much % noise because % is used for 3 things: the special
placeholder character inside format strings, the format operator and
the modulus operator.
--
http://mail.python.org/mailman/listinfo/python-list
RE: PEP 378: Format Specifier for Thousands Separator
Date: Thu, 23 May 2013 19:29:14 -0700 Subject: Re: PEP 378: Format Specifier for Thousands Separator From: dihedral88...@gmail.com [...] Could a separate instance like the I/O device of a subprocess to be easily available in Python? The next question would be whether the flow of several I/O data streams could be easily piped and manipulated in the high level programming designs without consuming too much resources. I'm sorry but I don't understand your question. Do you mean returning the output of another process to the caller? Like: import subprocess output = subprocess.check_output(['ping', 'google.com']) -- http://mail.python.org/mailman/listinfo/python-list
Re: PEP 378: Format Specifier for Thousands Separator
On 24.05.2013 17:25, Carlos Nepomuceno wrote: Date: Thu, 23 May 2013 19:29:14 -0700 Subject: Re: PEP 378: Format Specifier for Thousands Separator From: dihedral88...@gmail.com [some typical dihedral stuff] I'm sorry but I don't understand your question. Don't worry. I guess most people on this list don't understand it either. It looks like dihedral is a bot although nobody knows for sure. Search for some other posts from him/her/it in the archive and form your own opinion. IMHO you can simply ignore him/her/it. Bye, Andreas -- http://mail.python.org/mailman/listinfo/python-list
RE: PEP 378: Format Specifier for Thousands Separator
lol that reminds me of George! lol ;) Date: Fri, 24 May 2013 19:28:29 +0200 From: andiper...@gmail.com To: python-list@python.org Subject: Re: PEP 378: Format Specifier for Thousands Separator On 24.05.2013 17:25, Carlos Nepomuceno wrote: Date: Thu, 23 May 2013 19:29:14 -0700 Subject: Re: PEP 378: Format Specifier for Thousands Separator From: dihedral88...@gmail.com [some typical dihedral stuff] I'm sorry but I don't understand your question. Don't worry. I guess most people on this list don't understand it either. It looks like dihedral is a bot although nobody knows for sure. Search for some other posts from him/her/it in the archive and form your own opinion. IMHO you can simply ignore him/her/it. Bye, Andreas -- http://mail.python.org/mailman/listinfo/python-list -- http://mail.python.org/mailman/listinfo/python-list
Re: PEP 378: Format Specifier for Thousands Separator
On May 22, 6:31 pm, Carlos Nepomuceno carlosnepomuc...@outlook.com
wrote:
Date: Wed, 22 May 2013 13:26:23 -0700
Subject: Re: PEP 378: Format Specifier for Thousands Separator
From: prueba...@latinmail.com
To: python-l...@python.org
[...]
Maybe a cformat(formatstring, variables) function should be created
in the string module so people who prefer that can use it. I don't
mind the C formatting syntax but I don't like the fact that the %
operator does something totally different when the first variable is
an integer and the fact that it misbehaves if the second variable is a
tuple.
--
http://mail.python.org/mailman/listinfo/python-list
I still don't understand why % benefits from literals optimization
('%d'%12345) while '{:d}'.format(12345) doesn't.
What totally different you talking about? Please give me an example.
def eggs(spam, ham): return spam % ham
def milk(beef, steak): return beef.format(steak)
a='%s'
c=9
d=4
e=[1,2]
f=(3,5)
d='{}'
eggs(a,4)
'4'
eggs(c,4)
1
eggs(a,e)
'[1, 2]'
eggs(a,f)
Traceback (most recent call last):
File pyshell#29, line 1, in module
eggs(a,f)
File pyshell#1, line 1, in eggs
def eggs(spam, ham): return spam % ham
TypeError: not all arguments converted during string formatting
'%s'%(5%3)
'2'
milk(d,4)
'4'
milk(c,4)
Traceback (most recent call last):
File pyshell#53, line 1, in module
milk(c,4)
File pyshell#49, line 1, in milk
def milk(beef, steak): return beef.format(steak)
AttributeError: 'int' object has no attribute 'format'
milk(d,e)
'[1, 2]'
milk(d,f)
'(3, 5)'
'{}'.format(5%3)
'2'
--
http://mail.python.org/mailman/listinfo/python-list
RE: PEP 378: Format Specifier for Thousands Separator
Date: Thu, 23 May 2013 06:44:05 -0700 Subject: Re: PEP 378: Format Specifier for Thousands Separator From: prueba...@latinmail.com To: python-list@python.org [...] eggs(a,f) Traceback (most recent call last): File pyshell#29, line 1, in module eggs(a,f) File pyshell#1, line 1, in eggs def eggs(spam, ham): return spam % ham TypeError: not all arguments converted during string formatting '%s'%(5%3) '2' So % doesn't handle tuples! Why's that? Is it intentional (by design)? -- http://mail.python.org/mailman/listinfo/python-list
Re: PEP 378: Format Specifier for Thousands Separator
On 05/23/2013 11:26 AM, Carlos Nepomuceno wrote: Date: Thu, 23 May 2013 06:44:05 -0700 Subject: Re: PEP 378: Format Specifier for Thousands Separator From: prueba...@latinmail.com To: python-list@python.org [...] You left out the part where a and f are initialized: a='%s' f=(3,5) eggs(a,f) Traceback (most recent call last): File pyshell#29, line 1, in module eggs(a,f) File pyshell#1, line 1, in eggs def eggs(spam, ham): return spam % ham TypeError: not all arguments converted during string formatting '%s'%(5%3) '2' So % doesn't handle tuples! Why's that? Is it intentional (by design)? It's a conflict in the design. A tuple is used to supply multiple arguments to the % operator. So if you want to have a tuple as the first argument, you need to enclose it in another tuple. try the following: print a % (f,) The trouble is, it doesn't generalize very readily, so it's difficult to use in a function like eggs() -- DaveA -- http://mail.python.org/mailman/listinfo/python-list
Re: PEP 378: Format Specifier for Thousands Separator
On 5/23/2013 2:42 PM, Dave Angel wrote: On 05/23/2013 11:26 AM, Carlos Nepomuceno wrote: eggs(a,f) Traceback (most recent call last): File pyshell#29, line 1, in module eggs(a,f) File pyshell#1, line 1, in eggs def eggs(spam, ham): return spam % ham TypeError: not all arguments converted during string formatting '%s'%(5%3) '2' So % doesn't handle tuples! Why's that? Is it intentional (by design)? It's a conflict in the design. A tuple is used to supply multiple arguments to the % operator. So if you want to have a tuple as the first argument, you need to enclose it in another tuple. The problem is that interpolating 1 to many items into a string is *not* a binary operation. The needed hack to pretend that it is, using a tuple to represent multiple items rather than just itself, was one of the reasons for making string formatting a honest function, where multiple items to be formatted are passed as multiple arguments. -- http://mail.python.org/mailman/listinfo/python-list
RE: PEP 378: Format Specifier for Thousands Separator
To: python-list@python.org From: tjre...@udel.edu [...] It's a conflict in the design. A tuple is used to supply multiple arguments to the % operator. So if you want to have a tuple as the first argument, you need to enclose it in another tuple. The problem is that interpolating 1 to many items into a string is *not* a binary operation. The needed hack to pretend that it is, using a tuple to represent multiple items rather than just itself, was one of the reasons for making string formatting a honest function, where multiple items to be formatted are passed as multiple arguments. Thanks so much guys! Now I understand why some people hate %-formatting! I don't think that's a problem because there's no format specifier for tuples in the %-formatting definition[1]. So it's up to the user to make the necessary conversion. I still love the %-formatting style! Can str.format() do the following? f = '%d %d %d' v = '1,2,3' print f % eval(v) If yes, how? [1] http://docs.python.org/2/library/stdtypes.html#string-formatting -- http://mail.python.org/mailman/listinfo/python-list
Re: PEP 378: Format Specifier for Thousands Separator
On Thu, May 23, 2013 at 6:20 PM, Carlos Nepomuceno
carlosnepomuc...@outlook.com wrote:
Can str.format() do the following?
f = '%d %d %d'
v = '1,2,3'
print f % eval(v)
Sure:
Python 3.2.2 (default, Sep 4 2011, 09:51:08) [MSC v.1500 32 bit (Intel)]
on win32
f = {} {} {}
v = 1,2,3
print(f.format(*eval(v)))
1 2 3
The * unpacks the tuple returned from eval(), so that you get 3 separate
parameters passed to format(), instead of the single tuple.
--
Jerry
--
http://mail.python.org/mailman/listinfo/python-list
RE: PEP 378: Format Specifier for Thousands Separator
Thank you! Hail Eris!!! :)
Date: Thu, 23 May 2013 21:17:54 -0400
Subject: Re: PEP 378: Format Specifier for Thousands Separator
From: malaclyp...@gmail.com
To: carlosnepomuc...@outlook.com
CC: python-list@python.org
On Thu, May 23, 2013 at 6:20 PM, Carlos Nepomuceno
carlosnepomuc...@outlook.commailto:carlosnepomuc...@outlook.com
wrote:
Can str.format() do the following?
f = '%d %d %d'
v = '1,2,3'
print f % eval(v)
Sure:
Python 3.2.2 (default, Sep 4 2011, 09:51:08) [MSC v.1500 32 bit
(Intel)] on win32
f = {} {} {}
v = 1,2,3
print(f.format(*eval(v)))
1 2 3
The * unpacks the tuple returned from eval(), so that you get 3
separate parameters passed to format(), instead of the single tuple.
--
Jerry
--
http://mail.python.org/mailman/listinfo/python-list
Re: PEP 378: Format Specifier for Thousands Separator
Carlos Nepomuceno於 2013年5月22日星期三UTC+8上午2時49分28秒寫道：
From: alyssonbr...@gmail.com
Date: Tue, 21 May 2013 09:03:13 -0300
Subject: Re: PEP 378: Format Specifier for Thousands Separator
To: python-list@python.org
This work in 3.1+:
$ python3
Python 3.1.3 (r313:86834, Nov 28 2010, 11:28:10)
[GCC 4.4.5] on linux2
Type help, copyright, credits or license for more information.
one_number = 1234567
print('number={:,}'.format(one_number))
number=1,234,567
Thank you, but let me rephrase it. I'm already using str.format() but I'd
like to use '%' (BINARY_MODULO) operator instead.
I've looked into the source code of CPython 2.7.5 and I've found no evidence
of the thousands separator been implemented on formatint() in
Objects/unicodeobject.c.
I also didn't find the _PyString_FormatLong() used in formatlong(). Where is
_PyString_FormatLong() located?
So, the question is: Where would I change the CPython 2.7.5 source code to
enable '%' (BINARY_MODULO) to format using the thousands separator like
str.format() does, such as:
sys.stderr.write('%,d\n' % 1234567)
1,234,567
Could a separate instance like the I/O device of a subprocess
to be easily available in Python?
The next question would be whether the flow of several I/O data streams could
be easily piped and manipulated in the high level
programming designs without consuming too much resources.
--
http://mail.python.org/mailman/listinfo/python-list
Re: PEP 378: Format Specifier for Thousands Separator
Carlos Nepomuceno於 2013年5月22日星期三UTC+8上午11時38分45秒寫道：
From: steve+comp.lang.pyt...@pearwood.info
Subject: Re: PEP 378: Format Specifier for Thousands Separator
Date: Wed, 22 May 2013 03:08:54 +
To: python-list@python.org
[...]
So, the only alternative to have '%,d' % x rendering the thousands
separator output would a C source code modification?
That's one alternative. But the language you would be then running will
no longer be Python.
Another alternative would be to write a pre-processor that parses your
Python source code, extracts any reference to the above, and replaces it
with a call to the appropriate format call. But not only is that a lot of
work for very little gain, but it's also more or less impossible to do in
full generality. And again, what you are running will be something
different than Python, it will be Python plus a pre-processor.
Don't fight the language. You will lose.
Not fighting the language. In fact it's not even a language issue.
All I need is a standard library[1] improvement: %,d! That's all!
Just to put in perspective the performance difference of str.__mod__() and
str.format():
C:\Python27python -m timeit -cv -n1000 '%d'%12345
raw times: 0.386 0.38 0.373
1000 loops, best of 3: 0.0373 usec per loop
C:\Python27python -m timeit -cv -n1000 '{:d}'.format(12345)
raw times: 7.91 7.89 7.98
1000 loops, best of 3: 0.789 usec per loop
C:\Python27python -m timeit -cv -n1000 '{:,d}'.format(12345)
raw times: 8.7 8.67 8.78
1000 loops, best of 3: 0.867 usec per loop
That shows str.format() is 20 times slower than str.__mod__() for a simple
decimal integer literal formatting.
And it's additionally 10% slower if the thousands separator format specifier
(',') is used.
[1] I think that translates to Python source code in 'Objects/stringobject.c'
and maybe 'Objects/unicodeobject.c'
--
Steven
--
http://mail.python.org/mailman/listinfo/python-list
The conversions of the 32 bit integers and 64 bit floats
to the strings of the base 10 digits require an
efficint div and mod normally in the low level.
--
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Re: PEP 378: Format Specifier for Thousands Separator
Please stop perpetuating this myth, see http://mail.python.org/pipermail/python-dev/2012-February/116789.html and http://bugs.python.org/issue14123 What myth? The myth that % string formatting is deprecated. It is not deprecated. Skip didn't say that it was deprecated. I didn't mean to create a tempest in a teapot. I was away from comp.lang.python, python-bugs, and python-dev for a few years. In particular, I didn't ever see the aforementioned thread from Feb 2012. Had I known of that thread I would have worded the sentence which shall not be repeated differently. My apologies... Skip -- http://mail.python.org/mailman/listinfo/python-list
Re: PEP 378: Format Specifier for Thousands Separator
On 5/21/2013 11:38 PM, Carlos Nepomuceno wrote: From:steve+comp.lang.pyt...@pearwood.info Subject: Re: PEP 378: Format Specifier for Thousands Separator Date: Wed, 22 May 2013 03:08:54 + To:python-list@python.org [...] So, the only alternative to have '%,d' % x rendering the thousands separator output would a C source code modification? That's one alternative. But the language you would be then running will no longer be Python. Another alternative would be to write a pre-processor that parses your Python source code, extracts any reference to the above, and replaces it with a call to the appropriate format call. But not only is that a lot of work for very little gain, but it's also more or less impossible to do in full generality. And again, what you are running will be something different than Python, it will be Python plus a pre-processor. Don't fight the language. You will lose. Not fighting the language. In fact it's not even a language issue. All I need is a standard library[1] improvement: %,d! That's all! You have to keep in mind that 2.7 is not getting any new features, no matter how small they seem. If you create a patch that implements the comma flag in %-formatting, it *might* go into 3.x, but it will not go into 2.7. --Ned. -- http://mail.python.org/mailman/listinfo/python-list
RE: PEP 378: Format Specifier for Thousands Separator
Date: Wed, 22 May 2013 07:25:13 -0400
From: n...@nedbatchelder.com
[...]
You have to keep in mind that 2.7 is not getting any new features, no
matter how small they seem. If you create a patch that implements the
comma flag in %-formatting, it *might* go into 3.x, but it will not go
into 2.7.
--Ned.
No problem. I have just discovered i was measuring the wrong thing.
My test case is been optimized at compile time by CPython that treats '%d' %
12345 as a constant.
My use case is different because I almost have no literals been used with %
operator.
So my gain isn't that great. In fact it's faster with str.format() than %, and
it's even faster if I use the default format specifier.
C:\Python27python -m timeit -cv -n1000 -sv=12345 '%d'%v
raw times: 10.5 10.7 10.7
1000 loops, best of 3: 1.05 usec per loop
C:\Python27python -m timeit -cv -n1000 -sv=12345 '{:d}'.format(v)
raw times: 8.11 8.09 8.02
1000 loops, best of 3: 0.802 usec per loop
C:\Users\Josue\Documents\Pythonpython -m timeit -cv -n1000 -sv=12345
'{}'.format(v)
raw times: 5.3 5.5 5.62
1000 loops, best of 3: 0.53 usec per loop
Using variables (100% of cases) makes str.format() 50% faster than %.
--
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Re: PEP 378: Format Specifier for Thousands Separator
On Wed, 22 May 2013 05:45:12 -0500, Skip Montanaro wrote: I didn't mean to create a tempest in a teapot. I was away from comp.lang.python, python-bugs, and python-dev for a few years. In particular, I didn't ever see the aforementioned thread from Feb 2012. Had I known of that thread I would have worded the sentence which shall not be repeated differently. My apologies... No problem, it's not about you specifically, it's just that some of us fans of % formatting can be a tad sensitive about it, especially since the idea that it has been deprecated (or soon will be deprecated, or one day will be deprecated, and therefore code using it is bad) is relatively widespread on the Internet. Glad to have you back here! -- Steven -- http://mail.python.org/mailman/listinfo/python-list
Re: PEP 378: Format Specifier for Thousands Separator
On 5/22/2013 10:58 AM, Steven D'Aprano wrote: On Wed, 22 May 2013 05:45:12 -0500, Skip Montanaro wrote: I didn't mean to create a tempest in a teapot. I was away from comp.lang.python, python-bugs, and python-dev for a few years. In particular, I didn't ever see the aforementioned thread from Feb 2012. Had I known of that thread I would have worded the sentence which shall not be repeated differently. My apologies... No problem, it's not about you specifically, it's just that some of us fans of % formatting can be a tad sensitive about it, especially since the idea that it has been deprecated (or soon will be deprecated, or one day will be deprecated, and therefore code using it is bad) is relatively widespread on the Internet. Seems like maybe this should become a question in the Python FAQ. --Ned. Glad to have you back here! -- http://mail.python.org/mailman/listinfo/python-list
Re: PEP 378: Format Specifier for Thousands Separator
On May 22, 2:30 pm, Ned Batchelder n...@nedbatchelder.com wrote: On 5/22/2013 10:58 AM, Steven D'Aprano wrote: On Wed, 22 May 2013 05:45:12 -0500, Skip Montanaro wrote: I didn't mean to create a tempest in a teapot. I was away from comp.lang.python, python-bugs, and python-dev for a few years. In particular, I didn't ever see the aforementioned thread from Feb 2012. Had I known of that thread I would have worded the sentence which shall not be repeated differently. My apologies... No problem, it's not about you specifically, it's just that some of us fans of % formatting can be a tad sensitive about it, especially since the idea that it has been deprecated (or soon will be deprecated, or one day will be deprecated, and therefore code using it is bad) is relatively widespread on the Internet. Seems like maybe this should become a question in the Python FAQ. --Ned. Glad to have you back here! Maybe a cformat(formatstring, variables) function should be created in the string module so people who prefer that can use it. I don't mind the C formatting syntax but I don't like the fact that the % operator does something totally different when the first variable is an integer and the fact that it misbehaves if the second variable is a tuple. -- http://mail.python.org/mailman/listinfo/python-list
RE: PEP 378: Format Specifier for Thousands Separator
Date: Wed, 22 May 2013 13:26:23 -0700
Subject: Re: PEP 378: Format Specifier for Thousands Separator
From: prueba...@latinmail.com
To: python-list@python.org
[...]
Maybe a cformat(formatstring, variables) function should be created
in the string module so people who prefer that can use it. I don't
mind the C formatting syntax but I don't like the fact that the %
operator does something totally different when the first variable is
an integer and the fact that it misbehaves if the second variable is a
tuple.
--
http://mail.python.org/mailman/listinfo/python-list
I still don't understand why % benefits from literals optimization
('%d'%12345) while '{:d}'.format(12345) doesn't.
What totally different you talking about? Please give me an example.
--
http://mail.python.org/mailman/listinfo/python-list
Re: PEP 378: Format Specifier for Thousands Separator
On 22 May 2013 23:31, Carlos Nepomuceno carlosnepomuc...@outlook.com wrote:
I still don't understand why % benefits from literals optimization
('%d'%12345) while '{:d}'.format(12345) doesn't.
There's no reason why that optimisation can't happen in principle.
However no one has written a patch for it. Why don't you look into
what it would take to make it happen?
Oscar
--
http://mail.python.org/mailman/listinfo/python-list
RE: PEP 378: Format Specifier for Thousands Separator
From: oscar.j.benja...@gmail.com
Date: Thu, 23 May 2013 01:30:53 +0100
Subject: Re: PEP 378: Format Specifier for Thousands Separator
To: carlosnepomuc...@outlook.com
CC: prueba...@latinmail.com; python-list@python.org
On 22 May 2013 23:31, Carlos Nepomuceno carlosnepomuc...@outlook.com wrote:
I still don't understand why % benefits from literals optimization
('%d'%12345) while '{:d}'.format(12345) doesn't.
There's no reason why that optimisation can't happen in principle.
However no one has written a patch for it. Why don't you look into
what it would take to make it happen?
Oscar
Maybe I'll look into that later, but I couldn't even find how the hell they
made _Py_InsertThousandsGrouping() been called.
That's what I got when analysing % formating:
Thousands separator format specifier for str.__mod__()
==
@Objects/stringobject.c: implements formatint() for '%' processing
-Looking for code used in str.format()
@Objects/stringlib/formatter.h: implements str.format()
-It uses STRINGLIB_GROUPING() to do the job.
@Objects/stringlib/stringdefs.h: #define STRINGLIB_GROUPING
_PyString_InsertThousandsGrouping
@Objects/stringlib/unicodedefs.h: #define STRINGLIB_GROUPING
_PyUnicode_InsertThousandsGrouping
@Objects/stringobject.c: #define _Py_InsertThousandsGrouping
_PyString_InsertThousandsGrouping
@Objects/stringobject.h: declares _PyString_InsertThousandsGrouping()
@???: ??? _PyString_InsertThousandsGrouping ??? _Py_InsertThousandsGrouping
@Objects/stringlib/localeutil.h: implements _Py_InsertThousandsGrouping()
Let me explain what that means. I found no relating declarations/definitions
that turn _PyString_InsertThousandsGrouping into _Py_InsertThousandsGrouping.
So, I don't even know how that source code compiles without error.
:/ really strange...
Not to mention the lots of code inside header definition files! Weird
--
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Re: PEP 378: Format Specifier for Thousands Separator
This work in 3.1+:
$ python3
Python 3.1.3 (r313:86834, Nov 28 2010, 11:28:10)
[GCC 4.4.5] on linux2
Type help, copyright, credits or license for more information.
one_number = 1234567
print('number={:,}'.format(one_number))
number=1,234,567
paz e amor (love and peace),
Alysson Bruno
===
Palmas(TO)
Brasil
Blog: http://abruno.com
Twitter: http://twitter.com/alyssonbruno
Facebook: http://www.facebook.com/ProfessorAlyssonBruno
=
*Meu alterego Escritor:*
Leia alguns contos que escrevo, não esqueça de me dar sua opinião:
http://goo.gl/Wjn4p http://goo.gl/AXv1g
=
On Tue, May 21, 2013 at 2:44 AM, Ned Deily n...@acm.org wrote:
In article blu176-w10190cb892a0414c988a05d7...@phx.gbl,
Carlos Nepomuceno carlosnepomuc...@outlook.com wrote:
Is there a way to format integers with thousands separator (digit
grouping)
like the format specifier of str.format()?
I'm currently using the following:
sys.stdout.write('Number = %s\n' % '{:,.0f}'.format(x))
Number = 12,345
'x' is unsigned integer so it's like using a sledgehammer to crack a
nut!
I'd like to have something like:
sys.stdout.write('Number = %,u\n' % x)
Is that possible? How can I do it if not already available?
For Python 3.2+ or 2.7, why not just:
print('Number = {:,}'.format(x))
Number = 12,345
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RE: PEP 378: Format Specifier for Thousands Separator
From: alyssonbr...@gmail.com
Date: Tue, 21 May 2013 09:03:13 -0300
Subject: Re: PEP 378: Format Specifier for Thousands Separator
To: python-list@python.org
This work in 3.1+:
$ python3
Python 3.1.3 (r313:86834, Nov 28 2010, 11:28:10)
[GCC 4.4.5] on linux2
Type help, copyright, credits or license for more information.
one_number = 1234567
print('number={:,}'.format(one_number))
number=1,234,567
Thank you, but let me rephrase it. I'm already using str.format() but I'd like
to use '%' (BINARY_MODULO) operator instead.
I've looked into the source code of CPython 2.7.5 and I've found no evidence of
the thousands separator been implemented on formatint() in
Objects/unicodeobject.c.
I also didn't find the _PyString_FormatLong() used in formatlong(). Where is
_PyString_FormatLong() located?
So, the question is: Where would I change the CPython 2.7.5 source code to
enable '%' (BINARY_MODULO) to format using the thousands separator like
str.format() does, such as:
sys.stderr.write('%,d\n' % 1234567)
1,234,567
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Re: PEP 378: Format Specifier for Thousands Separator
On Tue, May 21, 2013 at 8:49 PM, Carlos Nepomuceno
carlosnepomuc...@outlook.com wrote:
Thank you, but let me rephrase it. I'm already using str.format() but I'd
like to use '%' (BINARY_MODULO) operator instead.
There is no real reason to do this. `str.format()` is the new shiny
thing you should be using all the time. Also, '%' is BINARY_MODULO
(where did you even get that name from?) if and only if you have two
numbers, and it performs the modulo division (eg. 27 % 5 = 2)
So, the question is: Where would I change the CPython 2.7.5 source code to
enable '%' (BINARY_MODULO) to format using the thousands separator like
str.format() does, such as:
sys.stderr.write('%,d\n' % 1234567)
1,234,567
This will make your code unportable and useless, depending on one
patch you made. Please don’t do that. Instead,
sys.stdout.write('Number = %s\n' % '{:,.0f}'.format(x))
Number = 12,345
'x' is unsigned integer so it's like using a sledgehammer to crack a nut!
In Python? Tough luck, every int is signed. And it isn’t just a
sledgehammer, it’s something worse. Just do that:
sys.stdout.write('Number = {:,.0f}\n'.format(x))
Much more peaceful.
You can also do a print, like everyone sane would. Where did you
learn Python from? “Python Worst Practice for Dummies”?
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Re: PEP 378: Format Specifier for Thousands Separator
Thank you, but let me rephrase it. I'm already using str.format() but I'd like to use '%' (BINARY_MODULO) operator instead. That's unlikely to change. If not deprecated already string interpolation using the modulo operator has lost favor to the string object's format method. You might be able to get by with a change of your LOCALE setting and/or a peek at the documentation for the locale module. Skip -- http://mail.python.org/mailman/listinfo/python-list
Re: PEP 378: Format Specifier for Thousands Separator
On 21/05/2013 20:13, Skip Montanaro wrote: Thank you, but let me rephrase it. I'm already using str.format() but I'd like to use '%' (BINARY_MODULO) operator instead. That's unlikely to change. If not deprecated already string interpolation using the modulo operator has lost favor to the string object's format method. Please stop perpetuating this myth, see http://mail.python.org/pipermail/python-dev/2012-February/116789.html and http://bugs.python.org/issue14123 -- If you're using GoogleCrap™ please read this http://wiki.python.org/moin/GoogleGroupsPython. Mark Lawrence -- http://mail.python.org/mailman/listinfo/python-list
RE: PEP 378: Format Specifier for Thousands Separator
From: kwpol...@gmail.com
Date: Tue, 21 May 2013 21:06:11 +0200
Subject: Re: PEP 378: Format Specifier for Thousands Separator
To: carlosnepomuc...@outlook.com
CC: python-list@python.org
On Tue, May 21, 2013 at 8:49 PM, Carlos Nepomuceno
carlosnepomuc...@outlook.com wrote:
Thank you, but let me rephrase it. I'm already using str.format() but I'd
like to use '%' (BINARY_MODULO) operator instead.
There is no real reason to do this. `str.format()` is the new shiny
thing you should be using all the time. Also, '%' is BINARY_MODULO
(where did you even get that name from?) if and only if you have two
numbers, and it performs the modulo division (eg. 27 % 5 = 2)
I did:
def fmt(s):
... return '%s' % s
...
import dis
dis.dis(fmt)
2 0 LOAD_CONST 1 ('%s')
3 LOAD_FAST 0 (s)
6 BINARY_MODULO
7 RETURN_VALUE
Then I've looked for 'BINARY_MODULO' in Python/ceval.c and found:
case BINARY_MODULO:
w = POP();
v = TOP();
if (PyString_CheckExact(v))
x = PyString_Format(v, w);
else
x = PyNumber_Remainder(v, w);
Then I've looked for 'PyString_Format' and found it in Objects/stringobject.c
Analysing the code of stringobject.c I've found formatint() and formatlong().
I'm not using str.format() because it's slower than '%' and because I love '%'.
str.format() looks like Java shit to me!
So, the question is: Where would I change the CPython 2.7.5 source code to
enable '%' (BINARY_MODULO) to format using the thousands separator like
str.format() does, such as:
sys.stderr.write('%,d\n' % 1234567)
1,234,567
This will make your code unportable and useless, depending on one
patch you made. Please don’t do that. Instead,
I'm just learning how to improve things! ;)
sys.stdout.write('Number = %s\n' % '{:,.0f}'.format(x))
Number = 12,345
'x' is unsigned integer so it's like using a sledgehammer to crack a nut!
In Python? Tough luck, every int is signed. And it isn’t just a
sledgehammer, it’s something worse. Just do that:
sys.stdout.write('Number = {:,.0f}\n'.format(x))
Much more peaceful.
Indeed! I just cut and pasted my code to create an example for the message. The
actual format operation isn't done at the sys.stdout.write().
You can also do a print, like everyone sane would. Where did you
learn Python from? “Python Worst Practice for Dummies”?
lol I'm learning from my big mistakes up to now and a ton of online tutorials,
besides Dive into Python (2004)[1], Python Programming (2012)[2] and
Programming Python, 3rd Ed (2006) [print]
print isn't thread safe. That's why I've chosen sys.stdout.write() -- it's
faster and thread safe by default.
I don't need any fancy formating, just need to send the string to screen.
[1] http://www.diveintopython.net/
[1] http://en.wikibooks.org/wiki/Python_Programming
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RE: PEP 378: Format Specifier for Thousands Separator
Analysing the code of stringobject.c I've found formatint() and formatlong(). I mean _PyString_FormatLong() -- http://mail.python.org/mailman/listinfo/python-list
Re: PEP 378: Format Specifier for Thousands Separator
On 2013.05.21 14:26, Mark Lawrence wrote: On 21/05/2013 20:13, Skip Montanaro wrote: Thank you, but let me rephrase it. I'm already using str.format() but I'd like to use '%' (BINARY_MODULO) operator instead. That's unlikely to change. If not deprecated already string interpolation using the modulo operator has lost favor to the string object's format method. Please stop perpetuating this myth, see http://mail.python.org/pipermail/python-dev/2012-February/116789.html and http://bugs.python.org/issue14123 What myth? People should indeed be using .format(), but no one said % formatting was going away soon. Also, the suggested change to the docs wasn't made and the issue is closed. The current docs do not say that % formatting isn't going to be deprecated, but it does mention its caveats and suggests .format(). If you are trying to say that % formatting will never ever go away, then you are wrong. It is highly unlikely to go away in a 3.x release, but /may/ get phased out in Python 4.0. -- CPython 3.3.2 | Windows NT 6.2.9200 / FreeBSD 9.1 -- http://mail.python.org/mailman/listinfo/python-list
Re: PEP 378: Format Specifier for Thousands Separator
On 05/21/2013 12:06 PM, Chris “Kwpolska” Warrick wrote:
On Tue, May 21, 2013 at 8:49 PM, Carlos Nepomuceno wrote:
Thank you, but let me rephrase it. I'm already using str.format() but I'd like
to use '%' (BINARY_MODULO) operator instead.
There is no real reason to do this. `str.format()` is the new shiny
thing you should be using all the time.
.format() is useful, and has it's place, but % formatting is not going away.
So, the question is: Where would I change the CPython 2.7.5 source code to
enable '%' (BINARY_MODULO) to format using the thousands separator like
str.format() does, such as:
-- sys.stderr.write('%,d\n' % 1234567)
1,234,567
This will make your code unportable and useless, depending on one
patch you made. Please don’t do that.
Agreed. Unless you're willing to have your programs either run differently, or not at all, on other systems this is the
wrong way to fix it.
Where did you learn Python from? “Python Worst Practice for Dummies”?
Chris Warrick,
Was that necessary? Useful? Helpful in any way? If you can't be civil, keep
your posts to yourself.
--
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RE: PEP 378: Format Specifier for Thousands Separator
To: python-list@python.org From: breamore...@yahoo.co.uk Subject: Re: PEP 378: Format Specifier for Thousands Separator Date: Tue, 21 May 2013 20:26:41 +0100 On 21/05/2013 20:13, Skip Montanaro wrote: Thank you, but let me rephrase it. I'm already using str.format() but I'd like to use '%' (BINARY_MODULO) operator instead. That's unlikely to change. If not deprecated already string interpolation using the modulo operator has lost favor to the string object's format method. I used to think str.__mod__() was going to be deprecated until Steven told me it was a myth! Think I got that idea from the own Python docs, but it's gone by now. Nevermind... The fact is I have no need for str.format(). It's slow and awkward. str.format() looks like COBOL/Java idiom to me. I love Python! '%' is much more cool!!! Please stop perpetuating this myth, see http://mail.python.org/pipermail/python-dev/2012-February/116789.html and http://bugs.python.org/issue14123 -- If you're using GoogleCrap™ please read this http://wiki.python.org/moin/GoogleGroupsPython. Mark Lawrence -- http://mail.python.org/mailman/listinfo/python-list -- http://mail.python.org/mailman/listinfo/python-list
RE: PEP 378: Format Specifier for Thousands Separator
Date: Tue, 21 May 2013 14:53:54 -0500
From: bahamutzero8...@gmail.com
To: python-list@python.org
[...]
What myth? People should indeed be using .format(), but no one said %
formatting was going away soon. Also, the suggested change to the docs
wasn't made and the issue is closed. The current docs do not say that %
formatting isn't going to be deprecated, but it does mention its
caveats and suggests .format(). If you are trying to say that % formatting
will never ever go away, then you are wrong. It is highly
unlikely to go away in a 3.x release, but /may/ get phased out in Python 4.0.
I vote for keeping str.__mod__()!
Anyway, is it possible to overload str.__mod__() without deriving a class? I
mean to have something like:
old_mod = str.__mod__
def new_mod(x):
global old_mod
try:
old_mod(x)
except ValueError, ex:
#catch ValueError: unsupported format character ',' (0x2c) at index 1
#process new '%,d' format here
return '{:,}'.format(x) #just to illustrate the behaviour. it would
have it's own faster code
str.__mod__ = new_mod #this raises TypeError: can't set attributes of
built-in/extension type 'str'
sys.stdout.write('num=%,d\n' % 1234567)
--
CPython 3.3.2 | Windows NT 6.2.9200 / FreeBSD 9.1
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Re: PEP 378: Format Specifier for Thousands Separator
On Tue, 21 May 2013 23:22:24 +0300, Carlos Nepomuceno wrote: Anyway, is it possible to overload str.__mod__() without deriving a class? I mean to have something like: No, not in Python. If you want to monkey-patch built-in classes on the fly, with all the troubles that causes, use Ruby. -- Steven -- http://mail.python.org/mailman/listinfo/python-list
RE: PEP 378: Format Specifier for Thousands Separator
From: steve+comp.lang.pyt...@pearwood.info Subject: Re: PEP 378: Format Specifier for Thousands Separator Date: Wed, 22 May 2013 02:42:56 + To: python-list@python.org On Tue, 21 May 2013 23:22:24 +0300, Carlos Nepomuceno wrote: Anyway, is it possible to overload str.__mod__() without deriving a class? I mean to have something like: No, not in Python. If you want to monkey-patch built-in classes on the fly, with all the troubles that causes, use Ruby. So, the only alternative to have '%,d' % x rendering the thousands separator output would a C source code modification? -- Steven -- http://mail.python.org/mailman/listinfo/python-list -- http://mail.python.org/mailman/listinfo/python-list
Re: PEP 378: Format Specifier for Thousands Separator
On Tue, 21 May 2013 14:53:54 -0500, Andrew Berg wrote: On 2013.05.21 14:26, Mark Lawrence wrote: Please stop perpetuating this myth, see http://mail.python.org/pipermail/python-dev/2012-February/116789.html and http://bugs.python.org/issue14123 What myth? The myth that % string formatting is deprecated. It is not deprecated. People should indeed be using .format(), If it is useful to them, and not too slow, or indeed if they merely want to. And if not, then not. This is a good case where the original poster *should* use str.format, since it does exactly what he wants, and % does not. Python gives you many tools, and the wise man uses the right tool for the job. Sometimes that is % and sometimes it is str.format and sometimes it is string.Template. That str.format looks like Java is irrelevant. Method call syntax is common in Python, and is not original to Java. Besides, Python looks like many languages: some parts look like Java, some parts look like C, some parts remind me of functional languages like Lisp and Haskell, and some parts look like Algol or Pascal. but no one said % formatting was going away soon. True, but only for the definition no one = all the people who insist that % is deprecated, or soon to be deprecated. Also, the suggested change to the docs wasn't made and the issue is closed. The current docs do not say that % formatting isn't going to be deprecated, but it does mention its caveats and suggests .format(). If you are trying to say that % formatting will never ever go away, then you are wrong. It is highly unlikely to go away in a 3.x release, but /may/ get phased out in Python 4.0. What happens in Python 4000 is irrelevant. If somebody is trying to future proof their code for a version that *may never exist*, and if it does exist is likely to be six or eight years away from even starting the design phase, they are wasting their time. It is hard enough to track a moving target, it is impossible to track a target that isn't even a gleam in GvR's eye yet. -- Steven -- http://mail.python.org/mailman/listinfo/python-list
Re: PEP 378: Format Specifier for Thousands Separator
On Wed, 22 May 2013 05:56:53 +0300, Carlos Nepomuceno wrote: From: steve+comp.lang.pyt...@pearwood.info Subject: Re: PEP 378: Format Specifier for Thousands Separator Date: Wed, 22 May 2013 02:42:56 + To: python-list@python.org On Tue, 21 May 2013 23:22:24 +0300, Carlos Nepomuceno wrote: Anyway, is it possible to overload str.__mod__() without deriving a class? I mean to have something like: No, not in Python. If you want to monkey-patch built-in classes on the fly, with all the troubles that causes, use Ruby. So, the only alternative to have '%,d' % x rendering the thousands separator output would a C source code modification? That's one alternative. But the language you would be then running will no longer be Python. Another alternative would be to write a pre-processor that parses your Python source code, extracts any reference to the above, and replaces it with a call to the appropriate format call. But not only is that a lot of work for very little gain, but it's also more or less impossible to do in full generality. And again, what you are running will be something different than Python, it will be Python plus a pre-processor. Don't fight the language. You will lose. -- Steven -- http://mail.python.org/mailman/listinfo/python-list
Re: PEP 378: Format Specifier for Thousands Separator
On 2013.05.21 21:59, Steven D'Aprano wrote: On Tue, 21 May 2013 14:53:54 -0500, Andrew Berg wrote: On 2013.05.21 14:26, Mark Lawrence wrote: Please stop perpetuating this myth, see http://mail.python.org/pipermail/python-dev/2012-February/116789.html and http://bugs.python.org/issue14123 What myth? The myth that % string formatting is deprecated. It is not deprecated. Skip didn't say that it was deprecated. but no one said % formatting was going away soon. True, but only for the definition no one = all the people who insist that % is deprecated, or soon to be deprecated. Perhaps I missed something, but who is insisting this? What happens in Python 4000 is irrelevant. If somebody is trying to future proof their code for a version that *may never exist*, and if it does exist is likely to be six or eight years away from even starting the design phase, they are wasting their time. It is hard enough to track a moving target, it is impossible to track a target that isn't even a gleam in GvR's eye yet. I think you misunderstand. I'm not suggesting that format() be used simply because % formatting could be deprecated at some unknown time years from now; I was clarifying the status of % formatting. -- CPython 3.3.2 | Windows NT 6.2.9200 / FreeBSD 9.1 -- http://mail.python.org/mailman/listinfo/python-list
RE: PEP 378: Format Specifier for Thousands Separator
From: steve+comp.lang.pyt...@pearwood.info
Subject: Re: PEP 378: Format Specifier for Thousands Separator
Date: Wed, 22 May 2013 03:08:54 +
To: python-list@python.org
[...]
So, the only alternative to have '%,d' % x rendering the thousands
separator output would a C source code modification?
That's one alternative. But the language you would be then running will
no longer be Python.
Another alternative would be to write a pre-processor that parses your
Python source code, extracts any reference to the above, and replaces it
with a call to the appropriate format call. But not only is that a lot of
work for very little gain, but it's also more or less impossible to do in
full generality. And again, what you are running will be something
different than Python, it will be Python plus a pre-processor.
Don't fight the language. You will lose.
Not fighting the language. In fact it's not even a language issue.
All I need is a standard library[1] improvement: %,d! That's all!
Just to put in perspective the performance difference of str.__mod__() and
str.format():
C:\Python27python -m timeit -cv -n1000 '%d'%12345
raw times: 0.386 0.38 0.373
1000 loops, best of 3: 0.0373 usec per loop
C:\Python27python -m timeit -cv -n1000 '{:d}'.format(12345)
raw times: 7.91 7.89 7.98
1000 loops, best of 3: 0.789 usec per loop
C:\Python27python -m timeit -cv -n1000 '{:,d}'.format(12345)
raw times: 8.7 8.67 8.78
1000 loops, best of 3: 0.867 usec per loop
That shows str.format() is 20 times slower than str.__mod__() for a simple
decimal integer literal formatting.
And it's additionally 10% slower if the thousands separator format specifier
(',') is used.
[1] I think that translates to Python source code in 'Objects/stringobject.c'
and maybe 'Objects/unicodeobject.c'
--
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PEP 378: Format Specifier for Thousands Separator
Is there a way to format integers with thousands separator (digit grouping)
like the format specifier of str.format()?
I'm currently using the following:
sys.stdout.write('Number = %s\n' % '{:,.0f}'.format(x))
Number = 12,345
'x' is unsigned integer so it's like using a sledgehammer to crack a nut!
I'd like to have something like:
sys.stdout.write('Number = %,u\n' % x)
Is that possible? How can I do it if not already available?
--
http://mail.python.org/mailman/listinfo/python-list
Re: PEP 378: Format Specifier for Thousands Separator
In article blu176-w10190cb892a0414c988a05d7...@phx.gbl,
Carlos Nepomuceno carlosnepomuc...@outlook.com wrote:
Is there a way to format integers with thousands separator (digit grouping)
like the format specifier of str.format()?
I'm currently using the following:
sys.stdout.write('Number = %s\n' % '{:,.0f}'.format(x))
Number = 12,345
'x' is unsigned integer so it's like using a sledgehammer to crack a nut!
I'd like to have something like:
sys.stdout.write('Number = %,u\n' % x)
Is that possible? How can I do it if not already available?
For Python 3.2+ or 2.7, why not just:
print('Number = {:,}'.format(x))
Number = 12,345
--
Ned Deily,
n...@acm.org
--
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