In Java? In awk? In Korn shell?
Different languages have differnent answers, so please provide a context.
For example, in ABAP (the SAP language) it's SPLIT x AT space INTO part1 part2.. But it could well be you need something else.
How can I split "HELLO WORLD" into "hello" AND "world" by a single command with <space> as delimiter and put in two strings s1 and s2 ..