Keyword Split String from String standard library does this.
Split String string, separator=None, max_split=-1
Splits the string using separator as a delimiter string.
If a separator is not given, any whitespace string is a separator. In that case also possible consecutive whitespace as well as leading and trailing whitespace is ignored.
Split words are returned as a list. If the optional max_split is given, at most max_split splits are done, and the returned list will have maximum max_split + 1 elements.
Examples:
@{words} = Split String ${string}
@{words} = Split String ${string} ,${SPACE}
To get single values from @{words} use common array syntax: @{words}[i]. i is the index of the selected value. Indexes start from zero.
Update:
Since Robot Framework 3.1 the way to access an item in list is: ${words}[i].