en.javascript.info/9-regular-expressions/09-regexp-groups/3-find-decimal-positive-numbers/solution.md
2019-04-02 14:01:44 +03:00

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An non-negative integer number is `pattern:\d+`. We should exclude `0` as the first digit, as we don't need zero, but we can allow it in further digits.
So that gives us `pattern:[1-9]\d*`.
A decimal part is: `pattern:\.\d+`.
Because the decimal part is optional, let's put it in parentheses with the quantifier `pattern:'?'`.
Finally we have the regexp: `pattern:[1-9]\d*(\.\d+)?`:
```js run
let reg = /[1-9]\d*(\.\d+)?/g;
let str = "1.5 0 -5 12. 123.4.";
alert( str.match(reg) ); // 1.5, 0, 12, 123.4
```