How to measure erratic pattern in a data set

[deleted_user]

I am trying to do an analysis on how to select a data set statistically which has less peaks and valleys or less erratic pattern. Can someone suggest is there any statistical tool that can help me on this.

I tried with standard deviation but it falied

[plf515]

This is a very interesting problem, but you need to be more precise in what you mean by peaks and valleys. It would also help if you could say more about what your data are.