deb-python-pint/pint/formatting.py

314 lines
9.7 KiB
Python

# -*- coding: utf-8 -*-
"""
pint.formatter
~~~~~~~~~~~~~~
Format units for pint.
:copyright: 2016 by Pint Authors, see AUTHORS for more details.
:license: BSD, see LICENSE for more details.
"""
from __future__ import division, unicode_literals, print_function, absolute_import
import re
from .babel_names import _babel_units, _babel_lengths
from pint.compat import babel_units, Loc, string_types
__JOIN_REG_EXP = re.compile("\{\d*\}")
def _join(fmt, iterable):
"""Join an iterable with the format specified in fmt.
The format can be specified in two ways:
- PEP3101 format with two replacement fields (eg. '{0} * {1}')
- The concatenating string (eg. ' * ')
"""
if not iterable:
return ''
if not __JOIN_REG_EXP.search(fmt):
return fmt.join(iterable)
miter = iter(iterable)
first = next(miter)
for val in miter:
ret = fmt.format(first, val)
first = ret
return first
_PRETTY_EXPONENTS = '⁰¹²³⁴⁵⁶⁷⁸⁹'
def _pretty_fmt_exponent(num):
"""Format an number into a pretty printed exponent.
"""
# TODO: Will not work for decimals
ret = '{0:n}'.format(num).replace('-', '')
for n in range(10):
ret = ret.replace(str(n), _PRETTY_EXPONENTS[n])
return ret
#: _FORMATS maps format specifications to the corresponding argument set to
#: formatter().
_FORMATS = {
'P': { # Pretty format.
'as_ratio': True,
'single_denominator': False,
'product_fmt': '·',
'division_fmt': '/',
'power_fmt': '{0}{1}',
'parentheses_fmt': '({0})',
'exp_call': _pretty_fmt_exponent,
},
'L': { # Latex format.
'as_ratio': True,
'single_denominator': True,
'product_fmt': r' \cdot ',
'division_fmt': r'\frac[{0}][{1}]',
'power_fmt': '{0}^[{1}]',
'parentheses_fmt': r'\left({0}\right)',
},
'H': { # HTML format.
'as_ratio': True,
'single_denominator': True,
'product_fmt': r' ',
'division_fmt': r'{0}/{1}',
'power_fmt': '{0}<sup>{1}</sup>',
'parentheses_fmt': r'({0})',
},
'': { # Default format.
'as_ratio': True,
'single_denominator': False,
'product_fmt': ' * ',
'division_fmt': ' / ',
'power_fmt': '{0} ** {1}',
'parentheses_fmt': r'({0})',
},
'C': { # Compact format.
'as_ratio': True,
'single_denominator': False,
'product_fmt': '*', # TODO: Should this just be ''?
'division_fmt': '/',
'power_fmt': '{0}**{1}',
'parentheses_fmt': r'({0})',
},
}
def formatter(items, as_ratio=True, single_denominator=False,
product_fmt=' * ', division_fmt=' / ', power_fmt='{0} ** {1}',
parentheses_fmt='({0})', exp_call=lambda x: '{0:n}'.format(x),
locale=None, babel_length='long', babel_plural_form='one'):
"""Format a list of (name, exponent) pairs.
:param items: a list of (name, exponent) pairs.
:param as_ratio: True to display as ratio, False as negative powers.
:param single_denominator: all with terms with negative exponents are
collected together.
:param product_fmt: the format used for multiplication.
:param division_fmt: the format used for division.
:param power_fmt: the format used for exponentiation.
:param parentheses_fmt: the format used for parenthesis.
:param locale: the locale object as defined in babel.
:param babel_length: the length of the translated unit, as defined in babel cldr.
:param babel_plural_form: the plural form, calculated as defined in babel.
:return: the formula as a string.
"""
if not items:
return ''
if as_ratio:
fun = lambda x: exp_call(abs(x))
else:
fun = exp_call
pos_terms, neg_terms = [], []
for key, value in sorted(items):
if locale and babel_length and babel_plural_form and key in _babel_units:
_key = _babel_units[key]
locale = Loc.parse(locale)
unit_patterns = locale._data['unit_patterns']
compound_unit_patterns = locale._data["compound_unit_patterns"]
plural = 'one' if abs(value) <= 0 else babel_plural_form
if babel_length not in _babel_lengths:
other_lengths = [
_babel_length for _babel_length in reversed(_babel_lengths) \
if babel_length != _babel_length
]
else:
other_lengths = []
for _babel_length in [babel_length] + other_lengths:
pat = unit_patterns.get(_key, {}).get(_babel_length, {}).get(plural)
if pat is not None:
key = pat.replace('{0}', '').strip()
break
division_fmt = compound_unit_patterns.get("per", {}).get(babel_length, division_fmt)
power_fmt = '{0}{1}'
exp_call = _pretty_fmt_exponent
if value == 1:
pos_terms.append(key)
elif value > 0:
pos_terms.append(power_fmt.format(key, fun(value)))
elif value == -1 and as_ratio:
neg_terms.append(key)
else:
neg_terms.append(power_fmt.format(key, fun(value)))
if not as_ratio:
# Show as Product: positive * negative terms ** -1
return _join(product_fmt, pos_terms + neg_terms)
# Show as Ratio: positive terms / negative terms
pos_ret = _join(product_fmt, pos_terms) or '1'
if not neg_terms:
return pos_ret
if single_denominator:
neg_ret = _join(product_fmt, neg_terms)
if len(neg_terms) > 1:
neg_ret = parentheses_fmt.format(neg_ret)
else:
neg_ret = _join(division_fmt, neg_terms)
return _join(division_fmt, [pos_ret, neg_ret])
# Extract just the type from the specification mini-langage: see
# http://docs.python.org/2/library/string.html#format-specification-mini-language
# We also add uS for uncertainties.
_BASIC_TYPES = frozenset('bcdeEfFgGnosxX%uS')
_KNOWN_TYPES = frozenset(list(_FORMATS.keys()) + ['~'])
def _parse_spec(spec):
result = ''
for ch in reversed(spec):
if ch == '~' or ch in _BASIC_TYPES:
continue
elif ch in _KNOWN_TYPES:
if result:
raise ValueError("expected ':' after format specifier")
else:
result = ch
elif ch.isalpha():
raise ValueError("Unknown conversion specified " + ch)
else:
break
return result
def format_unit(unit, spec, **kwspec):
if not unit:
return 'dimensionless'
spec = _parse_spec(spec)
fmt = dict(_FORMATS[spec])
fmt.update(kwspec)
if spec == 'L':
rm = [(r'\mathrm{{{0}}}'.format(u), p) for u, p in unit.items()]
result = formatter(rm, **fmt)
else:
result = formatter(unit.items(), **fmt)
if spec == 'L':
result = result.replace('[', '{').replace(']', '}')
return result
def siunitx_format_unit(units):
'''Returns LaTeX code for the unit that can be put into an siunitx command.'''
# NOTE: unit registry is required to identify unit prefixes.
registry = units._REGISTRY
def _tothe(power):
if isinstance(power, int) or (isinstance(power, float) and power.is_integer()):
if power == 1:
return ''
elif power == 2:
return r'\squared'
elif power == 3:
return r'\cubed'
else:
return r'\tothe{{{:d}}}'.format(int(power))
else:
# limit float powers to 3 decimal places
return r'\tothe{{{:.3f}}}'.format(power).rstrip('0')
lpos = []
lneg = []
# loop through all units in the container
for unit, power in sorted(units._units.items()):
# remove unit prefix if it exists
# siunitx supports \prefix commands
l = lpos if power >= 0 else lneg
prefix = None
for p in registry._prefixes.values():
p = str(p)
if len(p) > 0 and unit.find(p) == 0:
prefix = p
unit = unit.replace(prefix, '', 1)
if power < 0:
l.append(r'\per')
if prefix is not None:
l.append(r'\{0}'.format(prefix))
l.append(r'\{0}'.format(unit))
l.append(r'{0}'.format(_tothe(abs(power))))
return ''.join(lpos) + ''.join(lneg)
def remove_custom_flags(spec):
for flag in _KNOWN_TYPES:
if flag:
spec = spec.replace(flag, '')
return spec
def vector_to_latex(vec, fmtfun=lambda x: format(x, '.2f')):
return matrix_to_latex([vec], fmtfun)
def matrix_to_latex(matrix, fmtfun=lambda x: format(x, '.2f')):
ret = []
for row in matrix:
ret += [' & '.join(fmtfun(f) for f in row)]
return r'\begin{pmatrix}%s\end{pmatrix}' % '\\\\ \n'.join(ret)
def ndarray_to_latex_parts(ndarr, fmtfun=lambda x: format(x, '.2f'), dim=()):
if isinstance(fmtfun, string_types):
fmt = fmtfun
fmtfun = lambda x: format(x, fmt)
if ndarr.ndim == 1:
return [vector_to_latex(ndarr, fmtfun)]
if ndarr.ndim == 2:
return [matrix_to_latex(ndarr, fmtfun)]
else:
ret = []
if ndarr.ndim == 3:
header = ('arr[%s,' % ','.join('%d' % d for d in dim)) + '%d,:,:]'
for elno, el in enumerate(ndarr):
ret += [header % elno + ' = ' + matrix_to_latex(el, fmtfun)]
else:
for elno, el in enumerate(ndarr):
ret += ndarray_to_latex_parts(el, fmtfun, dim + (elno, ))
return ret
def ndarray_to_latex(ndarr, fmtfun=lambda x: format(x, '.2f'), dim=()):
return '\n'.join(ndarray_to_latex_parts(ndarr, fmtfun, dim))