Given a text spread sheet f and a pattern to
be matched to its header (first line in the file), the function
returns the matching columns names or indices of the
corresponding data.frame.
Arguments
- f
A connection object or a
characterstring to be read in withreadLines(f, n = 1).- pattern
A
characterstring containing a regular expression to be matched to the file's header.- ...
Additional parameters passed to
strsplitto split the file header into individual column names.- n
An
integerspecifying which line in filefto grep (get). Default is 1. Note that this argument must be named.
Value
Depending on value, the matching column names of
indices. In case of getEcols, a character of
column names.
Details
The function starts by reading the first line of the file (or connection)
f with readLines, then splits it
according to the optional ... arguments (it is important to
correctly specify strsplit's split character vector here)
and then matches pattern to the individual column names using
grep.
Similarly, getEcols can be used to explore the column names and
decide for the appropriate pattern value.
These functions are useful to check the parameters to be provided to
readMSnSet2.