104 lines
2.3 KiB
Python
104 lines
2.3 KiB
Python
# piker: trading gear for hackers
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# Copyright (C) 2018-present Tyler Goodlet (in stewardship of piker0)
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# This program is free software: you can redistribute it and/or modify
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# it under the terms of the GNU Affero General Public License as published by
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# the Free Software Foundation, either version 3 of the License, or
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# (at your option) any later version.
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# This program is distributed in the hope that it will be useful,
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# but WITHOUT ANY WARRANTY; without even the implied warranty of
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# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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# GNU Affero General Public License for more details.
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# You should have received a copy of the GNU Affero General Public License
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# along with this program. If not, see <https://www.gnu.org/licenses/>.
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"""
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Handy financial calculations.
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"""
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import math
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import itertools
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from bidict import bidict
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_mag2suffix = bidict({3: 'k', 6: 'M', 9: 'B'})
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def humanize(
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number: float,
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digits: int = 1
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) -> str:
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'''
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Convert large numbers to something with at most ``digits`` and
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a letter suffix (eg. k: thousand, M: million, B: billion).
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'''
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try:
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float(number)
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except ValueError:
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return '0'
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if not number or number <= 0:
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return str(round(number, ndigits=digits))
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mag = round(math.log(number, 10))
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if mag < 3:
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return str(round(number, ndigits=digits))
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maxmag = max(
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itertools.takewhile(
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lambda key: mag >= key, _mag2suffix
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)
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)
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return "{value}{suffix}".format(
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value=round(number/10**maxmag, ndigits=digits),
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suffix=_mag2suffix[maxmag],
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)
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def puterize(
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text: str,
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digits: int = 1,
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) -> float:
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'''Inverse of ``humanize()`` above.
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'''
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try:
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suffix = str(text)[-1]
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mult = _mag2suffix.inverse[suffix]
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value = text.rstrip(suffix)
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return round(float(value) * 10**mult, ndigits=digits)
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except KeyError:
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# no matching suffix try just the value
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return float(text)
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def pnl(
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init: float,
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new: float,
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) -> float:
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'''Calcuate the percentage change of some ``new`` value
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from some initial value, ``init``.
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'''
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if not (init and new):
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return 0
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return (new - init) / init
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def percent_change(
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init: float,
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new: float,
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) -> float:
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return pnl(init, new) * 100.
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