Hi @lambertus, the original datetime is formatted with ISO standard. I would try using the DateTimeConverter in this case, as in:

Hi @takashi, thanks for your fast reply! It works almost fine! I converted most records to a suitable output, ISO standard. However, I am left with 33 records which did not contain data. I would like to store them also in the attribute 'Ingebruikname'. Finally, I would like to have an attribute with a ISO standard date or empty.

I agree with @takashi.

However, you mentioned that you wanted to solve this using RegEx. In that case you can use e.g. @ReplaceRegEx(@Value(ingebruikname),^([0-9]{4}-[0-9]{2}-[0-9]{2}).+$,\\1). What you do is replacing the full string by the (first) set between ().

Another solution could be @Left(@Value(ingebruikname),10). This replaces the attribute value by the first 10 characters.

And you might as well use a DateTime function within an AttributeCreator or -Manager.

Thanks for your reply! I used the AttributeManager in combination with your RegEx which works fine :)

What does the last part of your RegEx mean: +$\\1 ?

What is it that you would like to store then, if you have no information?

And if you'd like to keep the original value, you could copy it using a AttributeCopier or -Manager before changing the attribute ingebruikname.

I tried to explain that in the post. It takes the first result that is contained between (). If you just wanted the numbers you could use e.g. @ReplaceRegEx(@Value(ingebruikname),^((0-9]{4})-((0-9]{2})-((0-9]{2}).+$,\\1\\2\\3)

In your example \\1 would be 2019, \\2 would be 01 and \\3 would be 11

My data is not that perfect. I want to leave the fields with no date empty or give them a default value like 9999.

In order to keep empty attribute as-is, set "Yes" to the Passthrough nulls, empties, or missing parameter, shown in the screenshot I posted.

If you are using an old version of FME, the transformer may not have that parameter. In that case, you can just connect both the Output port and the <Rejected> port together to the subsequent transformer.

If you need to replace the attribute value with 9999 when it doesn't start with the correct date format "yyyy-mm-dd", this workflow could also be available, for example.

Thanks @takashi! I am going to try how I far get.

Which transformer do you use to combine both these outputs?

I agree with @takashi: when working with dates and times, really try using the DateTime functions and transformers, rather than RegEx. RegEx is very powerful, but is also known to be a memory hogger when used a bit too leniently; in particular when using 'match-anythings' like .+ and .*

It depends on what you need to perform next. If you just want to check the result, for example, connect an Inspector and run.