作为输入,我有一个字符串和一个带颜色的间隔数组:
// 0123456789.123456789.123456789.123456789.123
const str = 'The quick brown fox jumps over the lazy dog.';
const colors = [
{from: 0, to: 8, color: 'red'},
{from: 10, to: 14, color: 'brown'},
{from: 16, to: 24, color: 'blue'},
{from: 20, to: 29, color: 'yellow'}
];
请注意,输入间隔可以相交!
作为输出,我想计算一个不相交间隔的数组,其中包含给定字符串的颜色和子字符串。呼叫应如下所示:
结果= colorizedStrings(str,colors,'defaultColor');
结果应如下所示:
[
{ from: 0, to: 8, sub: 'The quick', colors: ['red' ] },
{ from: 9, to: 9, sub: ' ', colors: ['defaultColor' ] },
{ from: 10, to: 14, sub: 'brown', colors: ['brown' ] },
{ from: 15, to: 15, sub: ' ', colors: ['defaultColor' ] },
{ from: 16, to: 19, sub: 'fox ', colors: ['blue' ] },
{ from: 20, to: 24, sub: 'jumps', colors: ['blue', 'yellow'] },
{ from: 25, to: 29, sub: ' over', colors: ['yellow' ] },
{ from: 30, to: 43, sub: ' the lazy dog.', colors: ['defaultColor' ] },
]
必要时,输出间隔包含一种以上的颜色。
我试图找到一个开放的Javascript库来计算区间交点。但是,我找不到一个简单而又小巧的库-库中总是包含一些奇特的东西(例如图形,图表等)。我在这里寻找“纯数学”。
可以帮我找到合适的解决方案吗?
答案 0 :(得分:4)
您可以映射字符并获取每个字符的颜色,然后减少此数组以获取相同颜色的簇。
function colorizedStrings(string, colors, defaultColor) {
return Array
.from(string, (sub, i) => {
var t = colors.filter(({ from, to }) => from <= i && i <= to).map(({ color }) => color);
return { sub, colors: t.length ? t : [defaultColor] };
})
.reduce((r, { sub, colors }, i) => {
var last = r[r.length - 1];
if (last && last.colors.join() === colors.join()) {
++last.to;
last.sub += sub;
} else {
r.push({ from: i, to: i, sub, colors });
}
return r;
}, []);
}
// 0123456789.123456789.123456789.123456789.123
var str = 'The quick brown fox jumps over the lazy dog.',
// ---------
// -----
// ---------
// ----------
colors = [{ from: 0, to: 8, color: 'red' }, { from: 10, to: 14, color: 'brown' }, { from: 16, to: 24, color: 'blue' }, { from: 20, to: 29, color: 'yellow' }],
result = colorizedStrings(str, colors, 'defaultColor');
console.log(result);
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在给定索引下存储颜色可能会更快一点。
function colorizedStrings(string, colors, defaultColor) {
var colorsAtIndex = [];
colors.forEach(({ from, to, color }) => {
do {
(colorsAtIndex[from] = colorsAtIndex[from] || []).push(color);
} while (from++ < to)
});
return Array
.from(string, (sub, i) => ({ sub, colors: colorsAtIndex[i] || [defaultColor] }))
.reduce((r, { sub, colors }, i) => {
var last = r[r.length - 1];
if (last && last.colors.join() === colors.join()) {
++last.to;
last.sub += sub;
} else {
r.push({ from: i, to: i, sub, colors });
}
return r;
}, []);
}
var str = 'The quick brown fox jumps over the lazy dog.',
colors = [{ from: 0, to: 8, color: 'red' }, { from: 10, to: 14, color: 'brown' }, { from: 16, to: 24, color: 'blue' }, { from: 20, to: 29, color: 'yellow' }],
result = colorizedStrings(str, colors, 'defaultColor');
console.log(result);
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最后(一个更复杂的版本,不使用单个字母和较短的循环)
function colorizedStrings(string, colors, defaultColor) {
const addColor = (array, color) => array.filter(v => v !== 'defaultColor').concat(color);
return colors.reduce((r, { from, to, color }) =>
r.reduce((s, o) => {
if (to < o.from || from > o.to) { // no appearance
s.push(o);
} else if (from <= o.from && to >= o.to) { // same part
o.colors = addColor(o.colors, color);
s.push(o);
} else if (from <= o.from && to <= o.to) { // split in two parts
s.push(
{ from: o.from, to: to, sub: string.slice(o.from, to + 1), colors: addColor(o.colors, color) },
{ from: to + 1, to: o.to, sub: string.slice(to + 1, o.to + 1), colors: o.colors }
);
} else if (o.from <= from && o.to <= to) { // split in two parts
s.push(
{ from: o.from, to: from, sub: string.slice(o.from, from), colors: o.colors },
{ from: from, to: o.to, sub: string.slice(from, o.to + 1), colors: addColor(o.colors, color) }
);
} else if (from > o.from && to < o.to) { // split in three parts
s.push(
{ from: o.from, to: from - 1, sub: string.slice(o.from, from), colors: o.colors },
{ from: from, to: to, sub: string.slice(from, to + 1), colors: addColor(o.colors, color) },
{ from: to + 1, to: o.to, sub: string.slice(to + 1, o.to + 1), colors: o.colors }
);
} else {
s.push(o);
}
return s;
}, []),
[{ from: 0, to: string.length - 1, sub: string, colors: ['defaultColor'] }]);
}
var str = 'The quick brown fox jumps over the lazy dog.',
colors = [{ from: 0, to: 8, color: 'red' }, { from: 10, to: 14, color: 'brown' }, { from: 16, to: 24, color: 'blue' }, { from: 20, to: 29, color: 'yellow' }],
result = colorizedStrings(str, colors, 'defaultColor');
console.log(result);
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