How do I generate a list with a specified increment step

Question

How do I generate a vector with a specified increment step  e g  2   For example  how do I produce the following  0  2  4  6  8  10

User · Answer

You can use scalar multiplication to modify each element in your vector.

> r <- 0:10 
> r <- r * 2
> r 
 [1]  0  2  4  6  8 10 12 14 16 18 20

or

> r <- 0:10 * 2 
> r 
 [1]  0  2  4  6  8 10 12 14 16 18 20

User · Answer

The following example shows benchmarks for a few alternatives   library rbenchmark    Note spelling   rbenchmark   not  benchmark  benchmark seq 0 1e6 by 2   0 5e5  2 seq int 0L 1e6L by 2L                          test replications elapsed  relative user self sys self    2           0 5e 05    2          100   0 587  3 536145     0 344    0 244    1     seq 0  1e6  by   2          100   2 760 16 626506     1 832    0 900    3 seq int 0  1e6  by   2          100   0 166  1 000000     0 056    0 096   In this case  seq int is the fastest method and seq the slowest  If performance of this step isn t that important  it still takes  lt  3 seconds to generate a sequence of 500 000 values   I might still use seq as the most readable solution

User · Answer

Executing seq 1  10  1  does what 1 10 does  You can change the last parameter of seq  i e  by  to be the step of whatever size you like    gt   a vector of even numbers  gt  seq 0  10  by 2    Explicitly specifying  by  only to increase readability   gt   1   0  2  4  6  8 10

[r] How do I generate a list with a specified increment step?

Examples related to r

Examples related to seq