Get Rows Before and After a Specific Value or Rowname

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.

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

Arguments

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.

Value

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

References

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

Author

Ananda Mahto

Examples

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)
#> [[1]]
#>               ID V1
#> rowname.AB.01  1 68
#> rowname.BC.02  2 39
#> rowname.AD.03  3  1
#> rowname.CD.04  4 34
#> 
#> [[2]]
#>               ID V1
#> rowname.CD.07  7 14
#> rowname.BC.08  8 82
#> rowname.BC.09  9 59
#> rowname.BC.10 10 51
#> rowname.AC.11 11 97
#> rowname.BC.12 12 85
#> 
getMyRows(dat1, c("AB", "AC"), -1:1, FALSE)
#> [[1]]
#>               ID V1
#> rowname.AB.01  1 68
#> rowname.BC.02  2 39
#> 
#> [[2]]
#>               ID V1
#> rowname.CD.04  4 34
#> rowname.AC.05  5 87
#> rowname.AC.06  6 43
#> 
#> [[3]]
#>               ID V1
#> rowname.AC.05  5 87
#> rowname.AC.06  6 43
#> rowname.CD.07  7 14
#> 
#> [[4]]
#>               ID V1
#> rowname.BC.10 10 51
#> rowname.AC.11 11 97
#> rowname.BC.12 12 85
#> 
#> [[5]]
#>               ID V1
#> rowname.BC.12 12 85
#> rowname.AB.13 13 21
#> rowname.CD.14 14 54
#> 
#> [[6]]
#>               ID V1
#> rowname.CD.14 14 54
#> rowname.AB.15 15 74
#> rowname.BC.16 16  7
#> 
#> [[7]]
#>               ID V1
#> rowname.BC.16 16  7
#> rowname.AB.17 17 73
#> rowname.CD.18 18 79
#> 
#> [[8]]
#>               ID V1
#> rowname.CD.18 18 79
#> rowname.AC.19 19 85
#> rowname.AD.20 20 37
#> 
#> [[9]]
#>               ID V1
#> rowname.AD.20 20 37
#> rowname.AC.21 21 89
#> rowname.CD.22 22 37
#> 
#> [[10]]
#>               ID V1
#> rowname.CD.23 23 34
#> rowname.AC.24 24 89
#> rowname.BD.25 25 44
#> 
getMyRows(dat1, c("AB", "AC"), c(-1, 1), FALSE)
#> [[1]]
#>               ID V1
#> rowname.BC.02  2 39
#> 
#> [[2]]
#>               ID V1
#> rowname.CD.04  4 34
#> rowname.AC.06  6 43
#> 
#> [[3]]
#>               ID V1
#> rowname.AC.05  5 87
#> rowname.CD.07  7 14
#> 
#> [[4]]
#>               ID V1
#> rowname.BC.10 10 51
#> rowname.BC.12 12 85
#> 
#> [[5]]
#>               ID V1
#> rowname.BC.12 12 85
#> rowname.CD.14 14 54
#> 
#> [[6]]
#>               ID V1
#> rowname.CD.14 14 54
#> rowname.BC.16 16  7
#> 
#> [[7]]
#>               ID V1
#> rowname.BC.16 16  7
#> rowname.CD.18 18 79
#> 
#> [[8]]
#>               ID V1
#> rowname.CD.18 18 79
#> rowname.AD.20 20 37
#> 
#> [[9]]
#>               ID V1
#> rowname.AD.20 20 37
#> rowname.CD.22 22 37
#> 
#> [[10]]
#>               ID V1
#> rowname.CD.23 23 34
#> rowname.BD.25 25 44
#>