[Python-ideas] Disallow "00000" as a synonym for "0"
ron3200 at gmail.com
Sun Jul 19 18:22:49 CEST 2015
On 07/18/2015 11:17 PM, Steven D'Aprano wrote:
> On Sat, Jul 18, 2015 at 03:40:28PM -0400, Ron Adam wrote:
>> >And then there is this...
>>>>> > >>>000.0
>>>>> > >>>000.1
> The parsing rules for floats are not the same as int,
Umm.. yes. But are they intentional different?
> and since floats
> always use decimal, never octal, there's no ambiguity or confusion from
> writing "0000.0000". I don't propose changing floats.
Me either. It seems to me int's should be relaxed to allow for leading
The most common use of leading zero's is when numbers in strings are used
and those numbers are sorted. Without the leading zero's the sort order
may not be in numerical order.
The int class supports using leading zero's in strings, but not in literal
form. (Although it may use a C string to int function when parsing it.)
File "<stdin>", line 1
SyntaxError: invalid token
It's common to cut and paste numerical data from text data. If you are
cutting numerical data from a table, then you may also need to remove all
the leading zeros. A macro can do that, but it complicates a simple cut
and paste operation.
Note that this does not effect the internal representation of ints, only
how python interprets the string literal during the compiling process.
A social reason for this limitation is that a number of other languages do
use a leading digit 0 to define octal numbers. And this helps catch silent
errors due to copying numbers directly in that case. (Python uses "0o" and
not just "0".)
In python, it just catches a possible silent error, when a 0onnn is
mistyped as 00nnn.
So this looks like it's a quick BDFL judgement call to me. (or other core
developer number specialist call.) I think the status quo wins by default
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