RPA(blueprism) date validation - regex

Question

I am trying to validate date which is coming from an excel sheet , the format should be in dd/mm/yyyy
i tried with regex pattern [0-9]{2}/[0-9]{2}/[0-9]{4}
but this won't work with single digit date and we since we cannot add 0 at start in excel sheet this pattern ain't working. (this is for blueprism tool which have a action for regex matching]

Answer 1

To build in the resiliency you require, you'll have to accept either 1 or 2 digits for both dd and mm:
[0-9]{1,2}/[0-9]{1,2}/[0-9]{4}

Answer 2

Since you are mentioning that you are working with BluePrism, are you sure that you really need Regex for validating dates? Because BP has built-in feature for that callable directly inside a Calc stage - checkout following example (you can see Expression of selected Calc stage in top Expression bar).
The function used for validating dates is IsDate([Some date as string]), result is saved into a Flag data-item.
After the check you can use that Flag data-item in a Decision block and do whatever you consider appropriate if a date is not an actual date.
Note: of course, if you are working with lists/datatables in a Code stage instead of iterating over a collection in process layout, then you need something else, but this might be still helpful.
In Code stage I would probably simply use DateTime.Parse(String) method which is able to automatically convert a date in a form of a String into a DateTime object instance; example:
' DateTime.Parse throws an Exception if parsing failed.
Dim valid As Boolean = False
Try
Dim d = DateTime.Parse(First_Date)
valid = True
Catch e As Exception
valid = False
End Try
See more about parsing dates using DateTime.Parse at MSDN: https://msdn.microsoft.com/en-us/library/1k1skd40(v=vs.110).aspx
There is also a nice post about parsing dates here: https://stackoverflow.com/a/18465222/7439802

Answer 3

In blue prism you can use
FormatDate(Now(), FormatOfDate)
For comparing two dates, initially Convert(" FormatDate ") in same format and then you can compare.
For " FormatDate " option you can refer Help of Blue prism and search for dateadd --> select the Calculation and decision