getMyRows: Get Rows Before and After a Specific Value or Rowname
In mrdwab/SOfun: Functions From Answers to R Questions on Stack Overflow

Description Usage Arguments Value Author(s) References Examples

Extracts (possibly overlapping) rows provided both a pattern or index position to match and a range specifying how many rows before and after the matched row.

1	getMyRows(data, pattern, range, isNumeric = TRUE)

`data`	The input `data.frame`.
`pattern`	Either the pattern to match in the `rownames` or the numeric position of the initial rows.
`range`	A vector indicating the range of rows you want to extract (in the form of `-2:3`). In this case, it would extract two rows before and three rows after the matched index or pattern. Alternatively, a specific vector (instead of a range) can be supplied, as in `c(-1, 1)` in which case only the previous and next row will be returned, but not the row itself.
`isNumeric`	Logical. Is `pattern` a numeric vector of row positions (`isNumeri = TRUE`) or is it a string value that needs to be matched against the `rownames`? Defaults to `TRUE`.

A list of data.frames with the relevant rows extracted.

Ananda Mahto

http://stackoverflow.com/a/13155669/1270695

set.seed(1)
dat1 <- data.frame(ID = 1:25, V1 = sample(100, 25, replace = TRUE))
rownames(dat1) <- paste("rowname", sample(apply(combn(LETTERS[1:4], 2),
                        2, paste, collapse = ""),
                        25, replace = TRUE),
                        sprintf("%02d", 1:25), sep = ".")
getMyRows(dat1, c(2, 10), -3:2)
getMyRows(dat1, c("AB", "AC"), -1:1, FALSE)
getMyRows(dat1, c("AB", "AC"), c(-1, 1), FALSE)