25 lines
684 B
Markdown
25 lines
684 B
Markdown
---
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title: reverseNumber
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tags: math,string,beginner
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firstSeen: 2020-07-17T16:41:28+03:00
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lastUpdated: 2020-09-18T21:19:23+03:00
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---
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Reverses a number.
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- Use `Object.prototype.toString()` to convert `n` to a string.
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- Use `String.prototype.split('')`, `Array.prototype.reverse()` and `String.prototype.join('')` to get the reversed value of `n` as a string.
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- Use `parseFloat()` to convert the string to a number and `Math.sign()` to preserve its sign.
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```js
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const reverseNumber = n =>
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parseFloat(`${n}`.split('').reverse().join('')) * Math.sign(n);
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```
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```js
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reverseNumber(981); // 189
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reverseNumber(-500); // -5
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reverseNumber(73.6); // 6.37
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reverseNumber(-5.23); // -32.5
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```
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