I have regular expressions that allow numbers from 0 to 999999999999999999.99 which is allow

1. After a point it will only be two-digit (eg. 151531.99)
2. Allow Integer like 1, 2, 3565, 48784, 87848541, 151515

I have found one regex which is [ ]?([0-9]*\.[0-9] |[0-9]) But it does not look above condition.

CodePudding user response：

This part |[0-9] is an alternative that matches a single digit.

In this part [0-9]*\.[0-9] the digits and to are optional so it can match a leading dot as well.

You can match 1-18 digits and optional dot and 2 digits. Using anchors to prevent a partial match.

^\ ?\d{1,18}(?:\.\d{2})?$

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