rails, how to get specific string from a sentences : i want to ask what is best method on rails to get specific string from a sentences?
example i have 
"My working time is: 3 hours and the job is finished"
"Bla2 time is: 6 hours and the job is still pending"
"Bla bla bla time is: 7 hours and the job is finished"

i want to take the number after words "time is: "
so the output is only number like: 3, 6, 7
any idea how to do it? Thanks