The syntax first:last:step yields a row
vector of consecutive integers from first to last counting
by step. The final :step is optional and
defaults to 1 when omitted.
Each of first, last, and step must be a scalar and should be an integer (any fractional part is discarded). Because ‘:’ has a high precedence, operands other than numeric literals must usually be parenthesized.
When step is positive (or omitted) and end < start, or if step is negative and end > start, then the result is an empty matrix. If step is 0, then PSPP reports an error.
Here are some examples:
1:6 | ⇒ | {1, 2, 3, 4, 5, 6} |
1:6:2 | ⇒ | {1, 3, 5} |
-1:-5:-1 | ⇒ | {-1, -2, -3, -4, -5} |
-1:-5 | ⇒ | {} |
2:1:0 | ⇒ | (error) |