46 lines
1.1 KiB
Markdown
46 lines
1.1 KiB
Markdown
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---
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title: Split a character string based on change of character
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---
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# Split a character string based on change of character
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---
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## Solutions
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<details><summary>Solution 1 (Click to Show/Hide)</summary>
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```javascript
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function split(str) {
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const concat = xs =>
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xs.length > 0 ? (() => {
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const unit = typeof xs[0] === 'string' ? '' : [];
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return unit.concat.apply(unit, xs);
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})() : [];
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const group = xs => groupBy((a, b) => a === b, xs);
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const groupBy = (f, xs) => {
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const dct = xs.slice(1)
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.reduce((a, x) => {
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const
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h = a.active.length > 0 ? a.active[0] : undefined,
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blnGroup = h !== undefined && f(h, x);
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return {
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active: blnGroup ? a.active.concat([x]) : [x],
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sofar: blnGroup ? a.sofar : a.sofar.concat([a.active])
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};
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}, {
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active: xs.length > 0 ? [xs[0]] : [],
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sofar: []
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});
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return dct.sofar.concat(dct.active.length > 0 ? [dct.active] : []);
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};
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const map = (f, xs) => xs.map(f);
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const stringChars = s => s.split('');
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return map(concat, group(stringChars(str)))
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}
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```
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</details>
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