Source code for pint.formatting
"""
pint.formatter
~~~~~~~~~~~~~~
Format units for pint.
:copyright: 2016 by Pint Authors, see AUTHORS for more details.
:license: BSD, see LICENSE for more details.
"""
import re
from .babel_names import _babel_lengths, _babel_units
from .compat import babel_parse
__JOIN_REG_EXP = re.compile(r"\{\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. '{} * {}')
- The concatenating string (eg. ' * ')
Parameters
----------
fmt : str
iterable :
Returns
-------
str
"""
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.
Parameters
----------
num : int
Returns
-------
str
"""
# TODO: Will not work for decimals
ret = f"{num:n}".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": "{}{}",
"parentheses_fmt": "({})",
"exp_call": _pretty_fmt_exponent,
},
"L": { # Latex format.
"as_ratio": True,
"single_denominator": True,
"product_fmt": r" \cdot ",
"division_fmt": r"\frac[{}][{}]",
"power_fmt": "{}^[{}]",
"parentheses_fmt": r"\left({}\right)",
},
"H": { # HTML format.
"as_ratio": True,
"single_denominator": True,
"product_fmt": r" ",
"division_fmt": r"{}/{}",
"power_fmt": "{}^{}",
"parentheses_fmt": r"({})",
},
"": { # Default format.
"as_ratio": True,
"single_denominator": False,
"product_fmt": " * ",
"division_fmt": " / ",
"power_fmt": "{} ** {}",
"parentheses_fmt": r"({})",
},
"C": { # Compact format.
"as_ratio": True,
"single_denominator": False,
"product_fmt": "*", # TODO: Should this just be ''?
"division_fmt": "/",
"power_fmt": "{}**{}",
"parentheses_fmt": r"({})",
},
}
[docs]def formatter(
items,
as_ratio=True,
single_denominator=False,
product_fmt=" * ",
division_fmt=" / ",
power_fmt="{} ** {}",
parentheses_fmt="({0})",
exp_call=lambda x: f"{x:n}",
locale=None,
babel_length="long",
babel_plural_form="one",
):
"""Format a list of (name, exponent) pairs.
Parameters
----------
items : list
a list of (name, exponent) pairs.
as_ratio : bool, optional
True to display as ratio, False as negative powers. (Default value = True)
single_denominator : bool, optional
all with terms with negative exponents are
collected together. (Default value = False)
product_fmt : str
the format used for multiplication. (Default value = " * ")
division_fmt : str
the format used for division. (Default value = " / ")
power_fmt : str
the format used for exponentiation. (Default value = "{} ** {}")
parentheses_fmt : str
the format used for parenthesis. (Default value = "({0})")
locale : str
the locale object as defined in babel. (Default value = None)
babel_length : str
the length of the translated unit, as defined in babel cldr. (Default value = "long")
babel_plural_form : str
the plural form, calculated as defined in babel. (Default value = "one")
exp_call : callable
(Default value = lambda x: f"{x:n}")
Returns
-------
str
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 = babel_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:
# Don't remove this positional! This is the format used in Babel
key = pat.replace("{0}", "").strip()
break
division_fmt = compound_unit_patterns.get("per", {}).get(
babel_length, division_fmt
)
power_fmt = "{}{}"
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")
def _parse_spec(spec):
result = ""
for ch in reversed(spec):
if ch == "~" or ch in _BASIC_TYPES:
continue
elif ch in list(_FORMATS.keys()) + ["~"]:
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:
if spec.endswith("%"):
return ""
else:
return "dimensionless"
spec = _parse_spec(spec)
fmt = dict(_FORMATS[spec])
fmt.update(kwspec)
if spec == "L":
# Latex
rm = [
(r"\mathrm{{{}}}".format(u.replace("_", r"\_")), p) for u, p in unit.items()
]
return formatter(rm, **fmt).replace("[", "{").replace("]", "}")
elif spec == "H":
# HTML (Jupyter Notebook)
rm = [(u.replace("_", r"\_"), p) for u, p in unit.items()]
return formatter(rm, **fmt)
else:
# Plain text
return formatter(unit.items(), **fmt)
[docs]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
lpick = 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:
lpick.append(r"\per")
if prefix is not None:
lpick.append(r"\{}".format(prefix))
lpick.append(r"\{}".format(unit))
lpick.append(r"{}".format(_tothe(abs(power))))
return "".join(lpos) + "".join(lneg)
def remove_custom_flags(spec):
for flag in list(_FORMATS.keys()) + ["~"]:
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, str):
fmt = fmtfun
fmtfun = lambda x: format(x, fmt)
if ndarr.ndim == 0:
_ndarr = ndarr.reshape(1)
return [vector_to_latex(_ndarr, fmtfun)]
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))
