Hi R Experts,

About the data:
My data consists of people (ID) with years of service (Yos) for each year. An ID can appear multiple times.
The data is sorted by ID then by Year.

Problem:
I need to extract ID data with non-sequential YoS rows. For example below that would be all rows for ID 33 and 16 since they have a non-sequential YoS.
To accomplish this I figured I could create a column called 'CheckVal' that takes current row YoS minus previous row YoS. The first instance for each ID will be 0. 'CheckVal' in the below data set was created in Excel. I want to know how to do this in R.
Is there a package I can use or specific function or set of functions I can use to accomplish this?

#My data looks like:
> testSeq

   ID Year YoS CheckVal dept

1  12 2010 1.1      0.0    A

2  12 2011 2.1      1.0    A

3  44 2009 1.4      0.0    C

4  44 2010 2.4      1.0    C

5  44 2011 3.4      1.0    B

6  33 2009 2.3      0.0    A

7  33 2010 4.4      2.1    A

8  16 2009 1.6      0.0    B

9  16 2010 2.6      1.0    B

10 16 2011 5.6      3.0    C

11 16 2012 6.6      1.0    A

#here is dput of data for R

Structure(list(ID = c(12, 12, 44, 44, 44, 33, 33, 16, 16, 16,

16), Year = c(2010, 2011, 2009, 2010, 2011, 2009, 2010, 2009,

2010, 2011, 2012), YoS = c(1.1, 2.1, 1.4, 2.4, 3.4, 2.3, 4.4,

1.6, 2.6, 5.6, 6.6), CheckVal = c(0, 1, 0, 1, 1, 0, 2.1, 0, 1,

3, 1), dept = structure(c(1L, 1L, 3L, 3L, 2L, 1L, 1L, 2L, 2L,

3L, 1L), .Label = c("A", "B", "C"), class = "factor")), .Names = c("ID",

"Year", "YoS", "CheckVal", "dept"), row.names = c(NA, 11L), class = "data.frame")

Dan
Workforce Analyst
LLNL

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