The Colon Operator:

If the values in the vector are regularly spaced, the colon operator is used to iterate through these values. For illustration, 1:5 results in all the integers from 1 to 5:

>> vec = 1:5

vec =

1  2  3  4  5

Note that in this situation, the brackets [ ] are not essential to define the vector.

With the colon operator, a step value can also be identified with the other colon, in the form (first: step: last). For illustration, to generate a vector with all the integers from 1 to 9 in steps of 2:

>> nv = 1:2:9

nv =

1  3  5  7  9