Stefan Selvage, 18, appeared at Scarborough Magistrates' Court via video link from HMP Doncaster on Tuesday January 21.
He was charged with two counts of assault by beating and one of theft, all in Manor Road on September 18 last year.
After admitting both charges of assault he was given four weeks' detention in a young offenders institute for the first, and three weeks for the second.
No separate penalty was given for the theft.