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type conversion based on parsed types; also add "f" and "n" types

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This commit is contained in:
Richard Jones
2011-11-18 18:02:55 +11:00
parent 50d103b5b2
commit 9d4c0cc9f6
2 changed files with 167 additions and 90 deletions
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README.rst
+30 -22
View File
@@ -17,7 +17,7 @@ Basic usage:
Format Syntax
-------------
Most of the `Format String Syntax`_ is supported with anonymous
A basic version of the `Format String Syntax`_ is supported with anonymous
(fixed-position), named and formatted fields::
{[field name]:[format spec]}
@@ -28,7 +28,9 @@ element indexes are supported (as they would make no sense.)
Numbered fields are also not supported: the result of parsing will include
the parsed fields in the order they are parsed.
The conversion of fields to types other than strings is not yet supported.
The conversion of fields to types other than strings is done based on the
type in the format specification, which mirrors the format() behaviour.
There are no "!" field conversions like format() has.
Some simple parse() format string examples:
@@ -58,26 +60,30 @@ supported.
The comma "," separator is not yet supported.
The types supported are the not the format() types but rather some of
those types b, o, h, x, X and also regular expression character group types
d, D, w, W, s, S and not the string format types. The format() types n, f,
F, e, E, g and G are not yet supported.
The types supported are a slightly different mix to the format() types.
Some format() types come directly over: d, n, f, b, o, h, x and X.
In addition some regular expression character group types
D, w, W, s and S are also available.
===== ==========================================
Type Characters Matched
===== ==========================================
w Letters and underscore
W Non-letter and underscore
s Whitespace
S Non-whitespace
d Digits (effectively integer numbers)
D Non-digit
b Binary numbers
o Octal numbers
h Hexadecimal numbers (lower and upper case)
x Lower-case hexadecimal numbers
X Upper-case hexadecimal numbers
===== ==========================================
The format() types %, F, e, E, g and G are not yet supported.
===== ========================================== =======
Type Characters Matched Output
===== ========================================== =======
w Letters and underscore str
W Non-letter and underscore str
s Whitespace str
S Non-whitespace str
d Digits (effectively integer numbers) int
D Non-digit str
n Numbers with thousands separators (, or .) int
f Fixed-point numbers float
b Binary numbers int
o Octal numbers int
h Hexadecimal numbers (lower and upper case) int
x Lower-case hexadecimal numbers int
X Upper-case hexadecimal numbers int
===== ========================================== =======
Do remember though that most often a straight type-less {} will suffice
where a more complex type specification might have been used.
@@ -86,7 +92,7 @@ So, for example, some typed parsing, and None resulting if the typing
does not match:
>>> parse('Our {:d} {:w} are...', 'Our 3 weapons are...')
<Result ('3', 'weapons') {}>
<Result (3, 'weapons') {}>
>>> parse('Our {:d} {:w} are...', 'Our three weapons are...')
None
@@ -110,6 +116,8 @@ examples. Run the tests with "python -m parse".
**Version history (in brief)**:
- 1.1.3 type conversion is automatic based on specified field types. Also added
"f" and "n" types.
- 1.1.2 refactored, added compile() and limited ``from parse import *``
- 1.1.1 documentation improvements
- 1.1.0 implemented more of the `Format Specification Mini-Language`_
parse.py
+137 -68
View File
@@ -21,7 +21,7 @@ Basic usage:
Format Syntax
-------------
Most of the `Format String Syntax`_ is supported with anonymous
A basic version of the `Format String Syntax`_ is supported with anonymous
(fixed-position), named and formatted fields::
{[field name]:[format spec]}
@@ -32,7 +32,9 @@ element indexes are supported (as they would make no sense.)
Numbered fields are also not supported: the result of parsing will include
the parsed fields in the order they are parsed.
The conversion of fields to types other than strings is not yet supported.
The conversion of fields to types other than strings is done based on the
type in the format specification, which mirrors the format() behaviour.
There are no "!" field conversions like format() has.
Some simple parse() format string examples:
@@ -62,26 +64,30 @@ supported.
The comma "," separator is not yet supported.
The types supported are the not the format() types but rather some of
those types b, o, h, x, X and also regular expression character group types
d, D, w, W, s, S and not the string format types. The format() types n, f,
F, e, E, g and G are not yet supported.
The types supported are a slightly different mix to the format() types.
Some format() types come directly over: d, n, f, b, o, h, x and X.
In addition some regular expression character group types
D, w, W, s and S are also available.
===== ==========================================
Type Characters Matched
===== ==========================================
w Letters and underscore
W Non-letter and underscore
s Whitespace
S Non-whitespace
d Digits (effectively integer numbers)
D Non-digit
b Binary numbers
o Octal numbers
h Hexadecimal numbers (lower and upper case)
x Lower-case hexadecimal numbers
X Upper-case hexadecimal numbers
===== ==========================================
The format() types %, F, e, E, g and G are not yet supported.
===== ========================================== =======
Type Characters Matched Output
===== ========================================== =======
w Letters and underscore str
W Non-letter and underscore str
s Whitespace str
S Non-whitespace str
d Digits (effectively integer numbers) int
D Non-digit str
n Numbers with thousands separators (, or .) int
f Fixed-point numbers float
b Binary numbers int
o Octal numbers int
h Hexadecimal numbers (lower and upper case) int
x Lower-case hexadecimal numbers int
X Upper-case hexadecimal numbers int
===== ========================================== =======
Do remember though that most often a straight type-less {} will suffice
where a more complex type specification might have been used.
@@ -90,7 +96,7 @@ So, for example, some typed parsing, and None resulting if the typing
does not match:
>>> parse('Our {:d} {:w} are...', 'Our 3 weapons are...')
<Result ('3', 'weapons') {}>
<Result (3, 'weapons') {}>
>>> parse('Our {:d} {:w} are...', 'Our three weapons are...')
None
@@ -114,6 +120,8 @@ examples. Run the tests with "python -m parse".
**Version history (in brief)**:
- 1.1.3 type conversion is automatic based on specified field types. Also added
"f" and "n" types.
- 1.1.2 refactored, added compile() and limited ``from parse import *``
- 1.1.1 documentation improvements
- 1.1.0 implemented more of the `Format Specification Mini-Language`_
@@ -123,7 +131,7 @@ examples. Run the tests with "python -m parse".
This code is copyright 2011 eKit.com Inc (http://www.ekit.com/)
See the end of the source file for the license of use.
'''
__version__ = '1.1.2'
__version__ = '1.1.3'
import re
import unittest
@@ -152,7 +160,7 @@ FORMAT_RE = re.compile('''
(?P<prefix>\#)?
(?P<width>(?P<zero>0)?[1-9]\d*)?
(\.(?P<precision>\d+))?
(?P<type>[bohxXwWdDsS])?
(?P<type>[nbohxXfwWdDsS])?
''', re.VERBOSE)
@@ -161,6 +169,8 @@ class Parser(object):
self._fixed_args = []
self._groups = 0
self._format = format
self._type_conversions = {}
self._group_checks = {}
self._expression = re.compile('^%s$' % PARSE_RE.sub(self.replace, format))
def __repr__(self):
@@ -172,9 +182,16 @@ class Parser(object):
m = self._expression.match(string)
if m is None:
return None
l = m.groups()
l = list(m.groups())
for n in self._fixed_args:
if n in self._type_conversions:
l[n] = self._type_conversions[n](l[n])
named = m.groupdict()
for k in named:
if k in self._type_conversions:
named[k] = self._type_conversions[k](named[k])
fixed = tuple(l[n] for n in self._fixed_args)
return Result(fixed, m.groupdict())
return Result(fixed, named)
def replace(self, match):
d = match.groupdict()
@@ -190,11 +207,13 @@ class Parser(object):
wrap = '(%s)'
if ':' in d['fixed']:
format = d['fixed'][2:-1]
group = self._groups
elif d['named']:
if ':' in d['named']:
name, format = d['named'].split(':')
else:
name = d['named']
group = name
wrap = '(?P<%s>%%s)' % name
else:
raise ValueError('format not recognised')
@@ -211,30 +230,42 @@ class Parser(object):
d = m.groupdict()
#print 'FORMAT', d
if d['type'] == 'o':
if d['type'] == 'n':
s = '\d{1,3}([,.]\d{3})*'
self._type_conversions[group] = lambda x: int(x.replace(',', '').replace('.', ''))
elif d['type'] == 'o':
s = '[0-7]'
self._type_conversions[group] = lambda x: int(x, 8)
elif d['type'] == 'b':
s = '[01]'
self._type_conversions[group] = lambda x: int(x, 2)
elif d['type'] == 'h':
s = '[0-9a-fA-F]'
self._type_conversions[group] = lambda x: int(x, 16)
elif d['type'] == 'x':
s = '[0-9a-f]'
self._type_conversions[group] = lambda x: int(x, 16)
elif d['type'] == 'X':
s = '[0-9A-F]'
self._type_conversions[group] = lambda x: int(x, 16)
elif d['type'] == 'f':
s = r'\d+\.\d+'
self._type_conversions[group] = float
elif d['type'] == 'd':
s = r'\d'
self._type_conversions[group] = int
elif d['type']:
s = r'\%s' % d['type']
else:
s = '.'
# TODO: number types still to support:
# n Number (with number separator characters)
# f Floating-point numbers
# e Exponent notation
# E Exponent notation with upper-case E
# g General number format with added nan, inf and -inf
# G General number format with upper-case E, NAN, INF and -INF
if d['type'] and d['type'] in 'dobhxX':
if d['type'] and d['type'] in 'nfdobhxX':
if d['prefix']:
if d['type'] == 'b':
s = '0b' + s
@@ -262,20 +293,25 @@ class Parser(object):
if d['sign']:
raise ValueError('sign in format must accompany "d" type')
if d['width']:
if d['zero']:
s = s + '{%s}' % d['width'][1:]
else:
s = s + '{%s}' % d['width']
else:
if not d['type'] or d['type'] not in 'fn':
# all other types need some form of character set repetition now
s = s + '+?'
# place into a group now
s = wrap % s
# prefix with zeros or spaces?
if d['zero']:
s = '0*' + s
elif d['width']:
# all we really care about is that if the format originally
# specified a width then there will probably be padding - without an
# explicit alignment that'll mean right alignment with spaces
# padding
if not d['align']:
d['align'] = '>'
# TODO handle precision
# we're just going to ignore precision...
#(\.(?P<precision>\d+))?
# TODO support '='
@@ -289,11 +325,11 @@ class Parser(object):
if fill in '.\+?*[](){}^$':
fill = '\\' + fill
if align == '<':
s = '%s%s+' % (s, fill)
s = '%s%s*' % (s, fill)
elif align == '>':
s = '%s+%s' % (fill, s)
s = '%s*%s' % (fill, s)
elif align == '^':
s = '%s+%s%s+' % (fill, s, fill)
s = '%s*%s%s*' % (fill, s, fill)
return s
@@ -375,22 +411,34 @@ class TestPattern(unittest.TestCase):
def test_beaker(self):
'skip some trailing whitespace'
s = PARSE_RE.sub(self.p.replace, '{:<}')
self.assertEquals(s, '(.+?) +')
self.assertEquals(s, '(.+?) *')
def test_left_fill(self):
'skip some trailing periods'
s = PARSE_RE.sub(self.p.replace, '{:.<}')
self.assertEquals(s, '(.+?)\.+')
self.assertEquals(s, '(.+?)\.*')
def test_bird(self):
'skip some trailing whitespace'
s = PARSE_RE.sub(self.p.replace, '{:>}')
self.assertEquals(s, ' +(.+?)')
self.assertEquals(s, ' *(.+?)')
def test_center(self):
'skip some surrounding whitespace'
s = PARSE_RE.sub(self.p.replace, '{:^}')
self.assertEquals(s, ' +(.+?) +')
self.assertEquals(s, ' *(.+?) *')
def test_float(self):
'skip test float expression generation'
_ = lambda s: PARSE_RE.sub(self.p.replace, s)
self.assertEquals(_('{:f}'), '(-?\d+\.\d+)')
self.assertEquals(_('{:+f}'), '([-+]?\d+\.\d+)')
def test_number_commas(self):
'skip number with commas generation'
_ = lambda s: PARSE_RE.sub(self.p.replace, s)
self.assertEquals(_('{:n}'), '(-?\\d{1,3}([,.]\\d{3})*)')
self.assertEquals(_('{:+n}'), '([-+]?\\d{1,3}([,.]\\d{3})*)')
def test_format(self):
def _(fmt, matches):
@@ -402,7 +450,7 @@ class TestPattern(unittest.TestCase):
self.assertEquals(d.get(k), matches[k],
'm["%s"]=%r, expect %r' % (k, d.get(k), matches[k]))
for t in 'obhdDwWsS':
for t in 'obhfdDwWsS':
_(t, dict(type=t))
_('10'+t, dict(type=t, width='10'))
_('05d', dict(type='d', width='05', zero='0'))
@@ -458,6 +506,8 @@ class TestParse(unittest.TestCase):
def test_typed(self):
'pull a named, typed values out of string'
r = parse('hello {:d} {:w}', 'hello 12 people')
self.assertEquals(r.fixed, (12, 'people'))
r = parse('hello {:w} {:w}', 'hello 12 people')
self.assertEquals(r.fixed, ('12', 'people'))
def test_typed_fail(self):
@@ -478,16 +528,18 @@ class TestParse(unittest.TestCase):
def test_named_typed(self):
'pull a named, typed values out of string'
r = parse('hello {number:d} {things}', 'hello 12 people')
self.assertEquals(r.named, dict(number=12, things='people'))
r = parse('hello {number:w} {things}', 'hello 12 people')
self.assertEquals(r.named, dict(number='12', things='people'))
def test_named_aligned_typed(self):
'pull a named, typed values out of string'
r = parse('hello {number:<d} {things}', 'hello 12 people')
self.assertEquals(r.named, dict(number='12', things='people'))
self.assertEquals(r.named, dict(number=12, things='people'))
r = parse('hello {number:>d} {things}', 'hello 12 people')
self.assertEquals(r.named, dict(number='12', things='people'))
self.assertEquals(r.named, dict(number=12, things='people'))
r = parse('hello {number:^d} {things}', 'hello 12 people')
self.assertEquals(r.named, dict(number='12', things='people'))
self.assertEquals(r.named, dict(number=12, things='people'))
def test_numbers(self):
'pull a numbers out of a string'
@@ -499,31 +551,48 @@ class TestParse(unittest.TestCase):
def n(fmt, s, e):
if parse(fmt, s) is not None:
self.fail('%r matched %r' % (fmt, s))
y('a {:d} b', 'a 12 b', '12')
y('a {:d} b', 'a -12 b', '-12')
y('a {:d} b', 'a 12 b', 12)
y('a {:5d} b', 'a 12 b', 12)
y('a {:d} b', 'a -12 b', -12)
n('a {:d} b', 'a +12 b', None)
y('a {:-d} b', 'a -12 b', '-12')
y('a {:-d} b', 'a -12 b', -12)
n('a {:-d} b', 'a +12 b', None)
y('a {:+d} b', 'a -12 b', '-12')
y('a {:+d} b', 'a +12 b', '+12')
y('a {: d} b', 'a -12 b', '-12')
y('a {: d} b', 'a 12 b', ' 12')
y('a {:+d} b', 'a -12 b', -12)
y('a {:+d} b', 'a +12 b', 12)
y('a {: d} b', 'a -12 b', -12)
y('a {: d} b', 'a 12 b', 12)
n('a {: d} b', 'a +12 b', None)
y('a {:b} b', 'a 101101 b', '101101')
y('a {:#b} b', 'a 0b101101 b', '0b101101')
y('a {:o} b', 'a 12345670 b', '12345670')
y('a {:#o} b', 'a 0o12345670 b', '0o12345670')
y('a {:h} b', 'a 1234567890abcdef b', '1234567890abcdef')
y('a {:h} b', 'a 1234567890ABCDEF b', '1234567890ABCDEF')
y('a {:#h} b', 'a 0x1234567890abcdef b', '0x1234567890abcdef')
y('a {:#h} b', 'a 0x1234567890ABCDEF b', '0x1234567890ABCDEF')
y('a {:x} b', 'a 1234567890abcdef b', '1234567890abcdef')
y('a {:X} b', 'a 1234567890ABCDEF b', '1234567890ABCDEF')
y('a {:#x} b', 'a 0x1234567890abcdef b', '0x1234567890abcdef')
y('a {:#X} b', 'a 0x1234567890ABCDEF b', '0x1234567890ABCDEF')
y('a {:n} b', 'a 100 b', 100)
y('a {:n} b', 'a 1,000 b', 1000)
y('a {:n} b', 'a 1.000 b', 1000)
y('a {:n} b', 'a -1,000 b', -1000)
y('a {:+n} b', 'a +1,000 b', 1000)
y('a {:n} b', 'a 10,000 b', 10000)
y('a {:n} b', 'a 100,000 b', 100000)
n('a {:n} b', 'a 100,00 b', None)
y('a {:05d} b', 'a 00001 b', '00001')
y('a {:f} b', 'a 12.0 b', 12.0)
y('a {:f} b', 'a -12.1 b', -12.1)
y('a {:-f} b', 'a -12.1 b', -12.1)
y('a {:+f} b', 'a +12.1 b', 12.1)
y('a {: f} b', 'a 12.1 b', 12.1)
n('a {:f} b', 'a 12 b', None)
y('a {:b} b', 'a 101101 b', 0b101101)
y('a {:#b} b', 'a 0b101101 b', 0b101101)
y('a {:o} b', 'a 12345670 b', 0o12345670)
y('a {:#o} b', 'a 0o12345670 b', 0o12345670)
y('a {:h} b', 'a 1234567890abcdef b', 0x1234567890abcdef)
y('a {:h} b', 'a 1234567890ABCDEF b', 0x1234567890ABCDEF)
y('a {:#h} b', 'a 0x1234567890abcdef b', 0x1234567890abcdef)
y('a {:#h} b', 'a 0x1234567890ABCDEF b', 0x1234567890ABCDEF)
y('a {:x} b', 'a 1234567890abcdef b', 0x1234567890abcdef)
y('a {:X} b', 'a 1234567890ABCDEF b', 0x1234567890ABCDEF)
y('a {:#x} b', 'a 0x1234567890abcdef b', 0x1234567890abcdef)
y('a {:#X} b', 'a 0x1234567890ABCDEF b', 0x1234567890ABCDEF)
y('a {:05d} b', 'a 00001 b', 1)
# TODO this should pass
# y('a {:05d} b', 'a 0000001 b', None)