rphast (version 1.0)

tagval: Extract value from tag-value formatted attributes...

Description

Extract value from tag-value formatted attributes

Usage

tagval(x, tag)

Arguments

x

A vector of character strings in tag-val format (as described in the GFF standard; ie, "tag1 val1a val1b; tag2 val2 ; ...", where vals are in quotes if they are strings.

tag

The tag whose values are to be extracted.

Value

• If there is at most one value per tag for each element of x, a character vector of the same length as x will be returned, containing the value for each element, or NA if the tag does not exist for that element. If some elements have multiple values, then the return value will be a list with the same length as x, each element being a character vector containing the values for the corresponding element of x (or NA for no value).

Examples

require("rphast")
tags <- c("tag1 "val 1a"; tag2 "val 2a" "val2a.1" 123; tag3 "val3a"",
          "tag1 "val 1b"; tag2 "val 2b"; tag4 "val4b"",
          "tag3 "val3a" 1; tag4 2;")
tagval(tags, "tag1")
tagval(tags, "tag2")
tagval(tags, "tag3")
tagval(tags, "tag4")
tagval(tags, "notag")
rm(tags)