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matemat/matemat/util/currency_format.py

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Python

def format_chf(value: int, with_currencysign: bool = True, plus_sign: bool = False) -> str:
"""
Formats a centime value into a commonly understood representation ("CHF -13.37").
:param value: The value to format, in centimes.
:param with_currencysign: Whether to include the currency prefix ("CHF ") in the output.
:param plus_sign: Whether to denote positive values with an explicit "+" sign before the value.
:return: A human-readable string representation.
"""
sign: str = ''
if value < 0:
# As // and % round towards -Inf, convert into a positive value and prepend the negative sign
sign = '-'
value = -value
elif plus_sign:
sign = '+'
# Split into full francs and fractions (centimes)
full: int = value // 100
frac: int = value % 100
csign: str = 'CHF ' if with_currencysign else ''
# Put it all together; centimes are always padded with 2 zeros
return f'{csign}{sign}{full}.{frac:02}'
def parse_chf(value: str) -> int:
"""
Parse a currency value into machine-readable format (integer centimes). The prefix "CHF", the decimal point, and
digits after the decimal point are optional.
:param value: The value to parse.
:return: An integer representation of the value.
:raises: Value error: If more than two digits after the decimal point are present.
"""
# Remove optional leading "CHF" and strip whitespace
value = value.strip()
if value.startswith('CHF'):
value = value[3:]
value = value.strip()
if '.' not in value:
# already is an integer; parse and turn into centimes
return int(value, 10) * 100
# Split at the decimal point
full, frac = value.split('.', 1)
if len(frac) > 2:
raise ValueError('Needs max. 2 digits after decimal point')
elif len(frac) < 2:
# Right-pad fraction with zeros ("x." -> "x.00", "x.x" -> "x.x0")
frac = frac + '0' * (2 - len(frac))
# Parse both parts
ifrac: int = int(frac, 10)
ifull: int = int(full, 10)
if ifrac < 0:
raise ValueError('Fraction part must not be negative.')
if full.startswith('-'):
ifrac = -ifrac
# Combine into centime integer
return ifull * 100 + ifrac