java - Regex to get first number in string with other characters

Question

I'm new to regular expressions, and was wondering how I could get only the first number in a string like 100 2011-10-20 14:28:55. In this case, I'd want it to return 100, but the number could also be shorter or longer.

I was thinking about something like [0-9]+, but it takes every single number separately (100,2001,10,...)

Thank you.

Answer 1

/^[^d]*(d+)/

This will start at the beginning, skip any non-digits, and match the first sequence of digits it finds

EDIT: this Regex will match the first group of numbers, but, as pointed out in other answers, parseInt is a better solution if you know the number is at the beginning of the string