Question

我找到了generate n distinct colors的代码。我拿了代码并用它做了一个课

import colorsys
import itertools
from fractions import Fraction

class DistinctColorsGenerator:
    def __init__(self):
        self._bias = lambda x: (math.sqrt(x / 3) / Fraction(2, 3) + Fraction(1, 3)) / Fraction(6, 5)
        self._gen_rgb = lambda x : colorsys.hsv_to_rgb(*x)
        self._flatten = itertools.chain.from_iterable
        self._hsvs = lambda: self._flatten(map(self._hsv, self._fracs()))
        self._rgbs = lambda: map(self._gen_rgb, self._hsvs())
        self._gen_colors = lambda: map(self._gen_color, self._rgbs())

    def generate(self, number):
        return list(itertools.islice(self._gen_colors(), number))

    def _zenos_dichotomy(self):
        for k in itertools.count():
            yield Fraction(1, 2 ** k)

    def _fracs(self):
        yield 0
        for k in self._zenos_dichotomy():
            i = k.denominator
            for j in range(1, i, 2):
                yield Fraction(j, i)

    def _hsv(self, h):
        for s in [Fraction(6, 10)]:
            for v in [Fraction(8, 10), Fraction(5, 10)]:
                yield (h, s, v)

    def _gen_color(self, x):
        uint8tuple = map(lambda y: int(y * 255), x)
        return list(uint8tuple)

我想将其转换为Kotlin，问题在于我的大部分Kotlin经验（以及Python）都在编写普通的无聊代码。而看起来这个通过生成无限序列并懒惰地评估它来解决问题。我可以看看Python代码，了解发生了什么，并编写一个简单而无聊的代码。但在此之前我想问一下是否有人可以展示如何在Kotlin中实现类似的东西

Answer 1

我阅读了一些文档（正如评论中所建议的那样），这就是我提出的（以防万一有人会发现它有用）

class DistinctColorsGenerator {
    fun generate(number: Int): List<ColorRgb> = generateRgbs.take(number).toList()

    private val genHsvs = buildSequence {
        fractions.forEach { createHsvColors(it).forEach { yield(it) } }
    }

    private val generateRgbs = buildSequence {
        genHsvs.forEach { yield(it.toRgb()) }
    }

    private val zenosDichotomy = buildSequence {
        var d = 1
        while (true) {
            yield(Fraction(1, d))
            d *= 2
        }
    }

    private val fractions = buildSequence {
        yield(Fraction(0, 1))
        zenosDichotomy.forEach {
            val i = it.denominator.toInt()
            for (j in 1 until i step 2) {
                yield(Fraction(j, i))
            }
        }
    }

    private fun createHsvColors(h: Fraction<Int>) = buildSequence {
        listOf(Fraction(6, 10)).forEach { s ->
            listOf(Fraction(8, 10), Fraction(5, 10)).forEach { v ->
                yield(ColorHsv(h, s, v))
            }
        }
    }
}

类ColorRgb，ColorHsv，Fraction只是数据类。 ColorHsv.toRgb()我从here

开始

将Python代码转换为Kotlin

1 个答案: