dbcolpercentile man page

dbcolpercentile — compute percentiles or ranks for an existing column

Synopsis

    dbcolpercentile [-rplhS] column

Description

Compute a percentile of a column of numbers. The new column will be called percentile or rank. Non-numeric records are handled as in other programs.

If the data is pre-sorted and only a rank is requested, no extra storage is required. In all other cases, a full copy of data is buffered on disk.

Options

-p or --percentile or --mode percentile: Show percentile (default). Percentile is the percentage of the cumulative values at or lower than the current value, relative to the total count.
-P or --rank or --nopercentile or --mode rank: Compute ranks instead of percentiles.
--fraction: Show fraction (percentage, except between 0 and 1, not cumulative fraction).
-a or --include-non-numeric: Compute stats over all records (treat non-numeric records as zero rather than just ignoring them).
-S or --pre-sorted: Assume data is already sorted. With one -S, we check and confirm this precondition. When repeated, we skip the check.
-f FORMAT or --format FORMAT: Specify a printf(3)-style format for output statistics. Defaults to %.5g.
-T TmpDir: where to put tmp files. Also uses environment variable TMPDIR, if -T is not specified. Default is /tmp.

Sort specification options (can be interspersed with column names):

-r or --descending: sort in reverse order (high to low)
-R or --ascending: sort in normal order (low to high)
-n or --numeric: sort numerically (default)
-N or --lexical: sort lexicographically

This module also supports the standard fsdb options:

-d: Enable debugging output.
-i or --input InputSource: Read from InputSource, typically a file name, or - for standard input, or (if in Perl) a IO::Handle, Fsdb::IO or Fsdb::BoundedQueue objects.
-o or --output OutputDestination: Write to OutputDestination, typically a file name, or - for standard output, or (if in Perl) a IO::Handle, Fsdb::IO or Fsdb::BoundedQueue objects.
--autorun or --noautorun: By default, programs process automatically, but Fsdb::Filter objects in Perl do not run until you invoke the run() method. The --(no)autorun option controls that behavior within Perl.
--help: Show help.
--man: Show full manual.

Sample Usage

Input

    #fsdb name id test1
    a 1 80
    b 2 70
    c 3 65
    d 4 90
    e 5 70
    f 6 90

Command

    cat DATA/grades.fsdb | dbcolpercentile test1

Output

        #fsdb name id test1 percentile
        d       4       90      1
        f       6       90      1
        a       1       80      0.66667
        b       2       70      0.5
        e       5       70      0.5
        c       3       65      0.16667
        #  | dbsort -n test1
        #   | dbcolpercentile test1

Command 2

    cat DATA/grades.fsdb | dbcolpercentile --rank test1

Output 2

        #fsdb name id test1 rank
        d       4       90      1
        f       6       90      1
        a       1       80      3
        b       2       70      4
        e       5       70      4
        c       3       65      6
        #  | dbsort -n test1
        #   | dbcolpercentile --rank test1