Anna Koroliuk added the comment:
Hi, all!
At Helsinki Python sprint I with the kind help of Ezio found two things.
1) This code gives results which are attached in the file. I will just now show
some interesting cases where isdigit() and isdecimal() give different results.
for c in map(chr, range(0x10)):
if unicodedata.digit(c, None) is not None: print(c, c.isdigit(), c.isdecimal())
...
0 True True
1 True True
2 True True
² True False
³ True False
¹ True False
፩ True False
፪ True False
፫ True False
፬ True False
① True False
② True False
③ True False
So it's different commands, although for usual digits 0-9 in usual typewriting
without those upper indexes etc they give same results. Full file
command_comparison.txt is attached.
2) Both commands isdigit() and isdecimal() are traced back that symbol is
compared to a certain tables (masks), but masks are different. For isdigit() it
is DIGIT_MASK = 0x04 and for isdecimal() is DECIMAL_MASK 0x02.
Here is how all the commands are traced to the mask.
A) isdecimal()
./Objects/unicodeobject.c:{"isdecimal", (PyCFunction) unicode_isdecimal,
METH_NOARGS, isdecimal__doc__},
./Objects/unicodeobject.c:
static PyObject*
unicode_isdecimal(PyObject *self)
if (length == 1)
return PyBool_FromLong(
Py_UNICODE_ISDECIMAL(PyUnicode_READ(kind, data, 0)));
./Include/unicodeobject.h:#define Py_UNICODE_ISDECIMAL(ch)
_PyUnicode_IsDecimalDigit(ch)
./Objects/unicodectype.c:
int _PyUnicode_IsDecimalDigit(Py_UCS4 ch)
{
if (_PyUnicode_ToDecimalDigit(ch) < 0)
return 0;
return 1;
}
int _PyUnicode_ToDecimalDigit(Py_UCS4 ch)
{
const _PyUnicode_TypeRecord *ctype = gettyperecord(ch);
return (ctype->flags & DECIMAL_MASK) ? ctype->decimal : -1;
}
./Objects/unicodectype.c:#define DECIMAL_MASK 0x02
B) isdigit()
./Objects/unicodeobject.c:{"isdigit", (PyCFunction) unicode_isdigit,
METH_NOARGS, isdigit__doc__},
./Objects/unicodeobject.c: static PyObject*
unicode_isdigit(PyObject *self)
...
if (length == 1) {
const Py_UCS4 ch = PyUnicode_READ(kind, data, 0);
return PyBool_FromLong(Py_UNICODE_ISDIGIT(ch));
}
./Include/unicodeobject.h:#define Py_UNICODE_ISDIGIT(ch) _PyUnicode_IsDigit(ch)
./Objects/unicodectype.c: int _PyUnicode_IsDigit(Py_UCS4 ch)
{
if (_PyUnicode_ToDigit(ch) < 0)
return 0;
return 1;
}
int _PyUnicode_ToDigit(Py_UCS4 ch)
{
const _PyUnicode_TypeRecord *ctype = gettyperecord(ch);
return (ctype->flags & DIGIT_MASK) ? ctype->digit : -1;
}
./Tools/unicode/makeunicodedata.py:DIGIT_MASK = 0x04
BR,
Anna
--
nosy: +Anna Koroliuk
Added file: http://bugs.python.org/file42149/command_comparison.txt
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