Updated Python code to make simplifications relying on Python 3 featu…

…res, on 10 pages: "Binary array set", "BitTorrent bencode format tools", "B-tree set", "Forcing a file's CRC to any value", "Free small FFT in multiple languages", "Gauss-Jordan elimination over any field", "Karatsuba multiplication", "Montgomery reduction algorithm", "Optimizing brainfuck compiler", "Windows timestamp accessor library".

binary-array-set/binaryarrayset.py

@@ -48,8 +48,7 @@ def clear(self):
 	def __iter__(self):
 		for vals in self.values:
 			if vals is not None:
-				for val in vals:
-					yield val
+				yield from vals
 
 
 	# Runs in O((log n)^2) time

bittorrent-bencode-format-tools/bencode.py

@@ -25,7 +25,6 @@
 Bencode supports four types of values:
 * Integer, which is mapped to Python int.
 * Byte string, which is mapped to Python bytes or bytearray.
-  (Note that in Python 2, bytes is a synonym for str.)
 * List, which is mapped to Python list or tuple, such that every element is a bencode value.
 * Dictionary, which is mapped to Python dict, such that every key
   is a bytes object and every value is a bencode value."""

bittorrent-bencode-format-tools/decode-bencode-demo.py

@@ -21,7 +21,6 @@
 #   Software.
 # 
 
-from __future__ import print_function
 import os, sys
 import bencode
 

btree-set/btreeset.py

@@ -167,8 +167,7 @@ def push_left_path(node):
 			node, index = stack.pop()
 			if node.is_leaf():
 				assert index == 0
-				for obj in node.keys:
-					yield obj
+				yield from node.keys
 			else:
 				yield node.keys[index]
 				index += 1

forcing-a-files-crc-to-any-value/forcecrc32.py

@@ -58,7 +58,7 @@ def main(args):
 
 # ---- Main function ----
 
-# Public library function. path is str/unicode, offset is uint, newcrc is uint32, printstatus is bool.
+# Public library function. path is str, offset is uint, newcrc is uint32, printstatus is bool.
 # Returns None. May raise IOError, ValueError, AssertionError.
 def modify_file_crc32(path, offset, newcrc, printstatus=False):
 	with open(path, "r+b") as raf:
@@ -107,7 +107,7 @@ def get_crc32(raf):
 	while True:
 		buffer = raf.read(128 * 1024)
 		if len(buffer) == 0:
-			return reverse32(crc & MASK)
+			return reverse32(crc)
 		crc = zlib.crc32(buffer, crc)
 
 

free-small-fft-in-multiple-languages/fft-test.py

@@ -111,7 +111,7 @@ def _naive_convolution(x, y):
 
 # ---- Utility functions ----
 
-_maxlogerr = float("-inf")
+_maxlogerr = -math.inf
 
 def _log10_rms_err(x, y):
 	global _maxlogerr

gauss-jordan-elimination-over-any-field/fieldmath.py

@@ -6,7 +6,7 @@
 # https://www.nayuki.io/page/gauss-jordan-elimination-over-any-field
 # 
 
-import fractions
+import fractions, math
 
 
 # ---- Field abstract class ----
@@ -366,7 +366,7 @@ def __init__(self, a, b, c, d):
 			a = -a
 			b = -b
 			c = -c
-		gcd = fractions.gcd(fractions.gcd(a, b), c)
+		gcd = math.gcd(math.gcd(a, b), c)
 		if gcd != 1:
 			a //= gcd
 			b //= gcd

karatsuba-multiplication/karatsuba.py

@@ -1,13 +1,11 @@
 # 
 # Karatsuba fast multiplication algorithm (Python)
 # 
-# Copyright (c) 2014 Project Nayuki
+# Copyright (c) 2020 Project Nayuki
 # All rights reserved. Contact Nayuki for licensing.
 # https://www.nayuki.io/page/karatsuba-multiplication
 # 
 
-# Requires Python version >= 2.7 because of long.bit_length().
-
 
 # Requirement: _CUTOFF >= 64, or else there will be infinite recursion.
 _CUTOFF = 1536

montgomery-reduction-algorithm/montgomery-reducer.py

@@ -6,7 +6,7 @@
 # https://www.nayuki.io/page/montgomery-reduction-algorithm
 # 
 
-import fractions, random, unittest
+import math, random, unittest
 
 
 class MontgomeryReducerTest(unittest.TestCase):
@@ -48,7 +48,7 @@ def __init__(self, mod):
 		self.reducerbits = (mod.bit_length() // 8 + 1) * 8  # This is a multiple of 8
 		self.reducer = 1 << self.reducerbits  # This is a power of 256
 		self.mask = self.reducer - 1
-		assert self.reducer > mod and fractions.gcd(self.reducer, mod) == 1
+		assert self.reducer > mod and math.gcd(self.reducer, mod) == 1
 
 		# Other computed numbers
 		self.reciprocal = MontgomeryReducer.reciprocal_mod(self.reducer % mod, mod)

optimizing-brainfuck-compiler/bfc.py

@@ -21,13 +21,13 @@ def main(args):
 
 	inname = args[0]
 	if not os.path.isfile(inname):
-		return inname + ": Not a file"
+		return f"{inname}: Not a file"
 
 	outname = args[1]
 	if   outname.endswith(".c"   ):  outfunc = commands_to_c
 	elif outname.endswith(".java"):  outfunc = commands_to_java
 	elif outname.endswith(".py"  ):  outfunc = commands_to_python
-	else:  return outname + ": Unknown output type"
+	else:  return f"{outname}: Unknown output type"
 
 	# Read input
 	with open(inname, "rt") as fin:

windows-timestamp-accessor-library/wintimestamp-demo.py

@@ -1,4 +1,3 @@
-# -*- coding: UTF-8 -*-
 # 
 # Windows timestamp accessor demo (Python)
 # 

windows-timestamp-accessor-library/wintimestamp.py

@@ -39,7 +39,7 @@ def __exit__(self, type, value, traceback):
 		self.close()
 
 
-	# Get-methods return the number of ticks as an int; path can be of type str or unicode
+	# Get-methods return the number of ticks as an int; path is of type str
 
 	def get_creation_time(self, path):
 		return self._get_some_time("Creation", path)
@@ -59,7 +59,7 @@ def _get_some_time(self, type, path):
 		return int(tokens[1])
 
 
-	# Set-methods require the number of ticks to be an int; path can be of type str or unicode
+	# Set-methods require the number of ticks to be an int; path is of type str
 
 	def set_creation_time(self, path, ticks):
 		self._set_some_time("Creation", path, ticks)