Day Validation using Regex

Question

I'm trying to use Regex to validate the days in a month. With this i am able to validate 01 to 31. How can i also validate 1-31, so that way i can either have 01 to 31 or 1 to 31

(0[1-9]|[12]\d|3[01])

@SebastianProske: OP does not have a clue, please provide an answer. — Wiktor Stribiżew, Oct 24 '16 at 19:26
A regex may not be the best solution. In what environment are you trying to validate the days in a month? Many languages have specific date functions which will do that for you. — Andrew Morton, Oct 24 '16 at 19:28
I'm trying to use C#, so I thought Regex would be a good choice or maybe using DateTime to also do this. — taji01, Oct 24 '16 at 19:32
The answer marked as duplicate is showing month, day and year. That is not what I wanted. I only wanted the to know how to do with Regex with the specified numbers I provided. — taji01, Oct 24 '16 at 19:49

Jithin Pavithran · Accepted Answer · 2016-10-24T19:45:07.060

1

Following will work for you.
(([12]\d)|(3[01])|(0?[1-9]))

I think you didn't understand the way your expression works.

Here it is:
| stands for OR.
Thus you have 3 cases here:

[12]\d
3[01]
0?[1-9]

1 - match either 1 or 2 as the 1st character and \d match any digit (same as [0-9]) as the second character.
2 - match 3 as the 1st digit. And either 0 or 1 as the second one.
3 - match with any digit between 1 to 9 (both included). 0? add an optional 0 as the 1st character.

edited Oct 24 '16 at 19:45

answered Oct 24 '16 at 19:33

Jithin Pavithran

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Its almost there, but it's not true if i type in 10 through 31. it works for 1 through 9 or 01 - 09. – taji01 Oct 24 '16 at 19:39
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The order is important. Answer is edited. – Jithin Pavithran Oct 24 '16 at 19:45

Day Validation using Regex

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