Remove a timestamp from string

Question

So I have been trying to take off a timestamp from a string, a file name to be more specific.

I tried making a substring, but the size of the timestamp is variable.

For example, sometimes it's like this:

2016-05-05 03:45:00.907text.txt

and sometimes like this:

2016-05-05 03:45:00.83text.txt

Maybe regex is the answer?

The string to be processed will always have a timestamp plus a filename. The filename can start with numbers or letters.

I forgot to say it's for Java.

Answer 1

String input = "2016-05-05 03:45:00.907text.txt";
String regex = "\\d{4}-\\d{2}-\\d{2} \\d{2}:\\d{2}:\\d{2}\\.\\d+";
SimpleDateFormat formatter = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss.SSSS");
Pattern pattern = Pattern.compile(regex);
Matcher matcher = pattern.matcher(input);

if(matcher.find()){
    String output  =  matcher.group();

    Date date = formatter.parse(output);
    long time = date.getTime();

    System.out.println(time);
}

You have to find the date with regex, then you convert the String in a proper Date and then you can get the timestamp.

Answer 2

this sed will cleanup the timestamp

$ echo "2016-05-05 03:45:00.83text.txt" | 
 sed -r 's/^[0-9]{4}(-[0-9]{2}){2} ([0-9]{2}:){2}[0-9]{2}\.[0-9]{2,3}//'

text.txt

will also work for the other case, however it will not know the difference if your file name is "7text.txt".