Skip to content

C
cpython
Commit cf59abc1 authored by Brett Cannon's avatar Brett Cannon
Browse files
Options

Remove the fpformat module.

parent 294d6d3d
Hide whitespace changes
Inline Side-by-side
Showing with 2 additions and 273 deletions
Doc/library/fpformat.rst deleted 100644 → 0
View file @ 294d6d3d
:mod:`fpformat` --- Floating point conversions
==============================================
.. module:: fpformat
:synopsis: General floating point formatting functions.
.. sectionauthor:: Moshe Zadka <moshez@zadka.site.co.il>
The :mod:`fpformat` module defines functions for dealing with floating point
numbers representations in 100% pure Python.
.. note::
This module is unnecessary: everything here can be done using the string
formatting functions described in the :ref:`string-formatting` section.
The :mod:`fpformat` module defines the following functions and an exception:
.. function:: fix(x, digs)
Format *x* as ``[-]ddd.ddd`` with *digs* digits after the point and at least one
digit before. If ``digs <= 0``, the decimal point is suppressed.
*x* can be either a number or a string that looks like one. *digs* is an
integer.
Return value is a string.
.. function:: sci(x, digs)
Format *x* as ``[-]d.dddE[+-]ddd`` with *digs* digits after the point and
exactly one digit before. If ``digs <= 0``, one digit is kept and the point is
suppressed.
*x* can be either a real number, or a string that looks like one. *digs* is an
integer.
Return value is a string.
.. exception:: NotANumber
Exception raised when a string passed to :func:`fix` or :func:`sci` as the *x*
parameter does not look like a number. This is a subclass of :exc:`ValueError`
when the standard exceptions are strings. The exception value is the improperly
formatted string that caused the exception to be raised.
Example::
>>> import fpformat
>>> fpformat.fix(1.23, 1)
'1.2'
Lib/fpformat.py deleted 100644 → 0
View file @ 294d6d3d
"""General floating point formatting functions.
Functions:
fix(x, digits_behind)
sci(x, digits_behind)
Each takes a number or a string and a number of digits as arguments.
Parameters:
x: number to be formatted; or a string resembling a number
digits_behind: number of digits behind the decimal point
"""
import re
__all__ = ["fix","sci","NotANumber"]
# Compiled regular expression to "decode" a number
decoder = re.compile(r'^([-+]?)0*(\d*)((?:\.\d*)?)(([eE][-+]?\d+)?)$')
# \0 the whole thing
# \1 leading sign or empty
# \2 digits left of decimal point
# \3 fraction (empty or begins with point)
# \4 exponent part (empty or begins with 'e' or 'E')
try:
class NotANumber(ValueError):
pass
except TypeError:
NotANumber = 'fpformat.NotANumber'
def extract(s):
"""Return (sign, intpart, fraction, expo) or raise an exception:
sign is '+' or '-'
intpart is 0 or more digits beginning with a nonzero
fraction is 0 or more digits
expo is an integer"""
res = decoder.match(s)
if res is None: raise NotANumber(s)
sign, intpart, fraction, exppart = res.group(1,2,3,4)
if sign == '+': sign = ''
if fraction: fraction = fraction[1:]
if exppart: expo = int(exppart[1:])
else: expo = 0
return sign, intpart, fraction, expo
def unexpo(intpart, fraction, expo):
"""Remove the exponent by changing intpart and fraction."""
if expo > 0: # Move the point left
f = len(fraction)
intpart, fraction = intpart + fraction[:expo], fraction[expo:]
if expo > f:
intpart = intpart + '0'*(expo-f)
elif expo < 0: # Move the point right
i = len(intpart)
intpart, fraction = intpart[:expo], intpart[expo:] + fraction
if expo < -i:
fraction = '0'*(-expo-i) + fraction
return intpart, fraction
def roundfrac(intpart, fraction, digs):
"""Round or extend the fraction to size digs."""
f = len(fraction)
if f <= digs:
return intpart, fraction + '0'*(digs-f)
i = len(intpart)
if i+digs < 0:
return '0'*-digs, ''
total = intpart + fraction
nextdigit = total[i+digs]
if nextdigit >= '5': # Hard case: increment last digit, may have carry!
n = i + digs - 1
while n >= 0:
if total[n] != '9': break
n = n-1
else:
total = '0' + total
i = i+1
n = 0
total = total[:n] + chr(ord(total[n]) + 1) + '0'*(len(total)-n-1)
intpart, fraction = total[:i], total[i:]
if digs >= 0:
return intpart, fraction[:digs]
else:
return intpart[:digs] + '0'*-digs, ''
def fix(x, digs):
"""Format x as [-]ddd.ddd with 'digs' digits after the point
and at least one digit before.
If digs <= 0, the point is suppressed."""
if type(x) != type(''): x = repr(x)
try:
sign, intpart, fraction, expo = extract(x)
except NotANumber:
return x
intpart, fraction = unexpo(intpart, fraction, expo)
intpart, fraction = roundfrac(intpart, fraction, digs)
while intpart and intpart[0] == '0': intpart = intpart[1:]
if intpart == '': intpart = '0'
if digs > 0: return sign + intpart + '.' + fraction
else: return sign + intpart
def sci(x, digs):
"""Format x as [-]d.dddE[+-]ddd with 'digs' digits after the point
and exactly one digit before.
If digs is <= 0, one digit is kept and the point is suppressed."""
if type(x) != type(''): x = repr(x)
sign, intpart, fraction, expo = extract(x)
if not intpart:
while fraction and fraction[0] == '0':
fraction = fraction[1:]
expo = expo - 1
if fraction:
intpart, fraction = fraction[0], fraction[1:]
expo = expo - 1
else:
intpart = '0'
else:
expo = expo + len(intpart) - 1
intpart, fraction = intpart[0], intpart[1:] + fraction
digs = max(0, digs)
intpart, fraction = roundfrac(intpart, fraction, digs)
if len(intpart) > 1:
intpart, fraction, expo = \
intpart[0], intpart[1:] + fraction[:-1], \
expo + len(intpart) - 1
s = sign + intpart
if digs > 0: s = s + '.' + fraction
e = repr(abs(expo))
e = '0'*(3-len(e)) + e
if expo < 0: e = '-' + e
else: e = '+' + e
return s + 'e' + e
def test():
"""Interactive test run."""
try:
while 1:
x, digs = input('Enter (x, digs): ')
print(x, fix(x, digs), sci(x, digs))
except (EOFError, KeyboardInterrupt):
pass
Lib/test/test_fpformat.py deleted 100644 → 0
View file @ 294d6d3d
'''
Tests for fpformat module
Nick Mathewson
'''
from test.test_support import run_unittest
import unittest
from fpformat import fix, sci, NotANumber
StringType = type('')
# Test the old and obsolescent fpformat module.
#
# (It's obsolescent because fix(n,d) == "%.*f"%(d,n) and
# sci(n,d) == "%.*e"%(d,n)
# for all reasonable numeric n and d, except that sci gives 3 exponent
# digits instead of 2.
#
# Differences only occur for unreasonable n and d. <.2 wink>)
class FpformatTest(unittest.TestCase):
def checkFix(self, n, digits):
result = fix(n, digits)
if isinstance(n, StringType):
n = repr(n)
expected = "%.*f" % (digits, float(n))
self.assertEquals(result, expected)
def checkSci(self, n, digits):
result = sci(n, digits)
if isinstance(n, StringType):
n = repr(n)
expected = "%.*e" % (digits, float(n))
# add the extra 0 if needed
num, exp = expected.split("e")
if len(exp) < 4:
exp = exp[0] + "0" + exp[1:]
expected = "%se%s" % (num, exp)
self.assertEquals(result, expected)
def test_basic_cases(self):
self.assertEquals(fix(100.0/3, 3), '33.333')
self.assertEquals(sci(100.0/3, 3), '3.333e+001')
def test_reasonable_values(self):
for d in range(7):
for val in (1000.0/3, 1000, 1000.0, .002, 1.0/3, 1e10):
for realVal in (val, 1.0/val, -val, -1.0/val):
self.checkFix(realVal, d)
self.checkSci(realVal, d)
def test_failing_values(self):
# Now for 'unreasonable n and d'
self.assertEquals(fix(1.0, 1000), '1.'+('0'*1000))
self.assertEquals(sci("1"+('0'*1000), 0), '1e+1000')
# This behavior is inconsistent. sci raises an exception; fix doesn't.
yacht = "Throatwobbler Mangrove"
self.assertEquals(fix(yacht, 10), yacht)
try:
sci(yacht, 10)
except NotANumber:
pass
else:
self.fail("No exception on non-numeric sci")
def test_main():
run_unittest(FpformatTest)
if __name__ == "__main__":
test_main()
Misc/NEWS
View file @ cf59abc1
......@@ -21,6 +21,8 @@ Extension Modules
Library
-------
- The fpformat module has been removed.
- The dircache module has been removed.
- The Canvas module has been removed.
......
Markdown is supported
0% or
You are about to add 0 people to the discussion. Proceed with caution.
Finish editing this message first!
Please register or to comment
GitLab Nexedi Edition | About GitLab | About Nexedi | 沪ICP备2021021310号-2 | 沪ICP备2021021310号-7