R: Number of days (less than, greater than, etc) a threshold

number.days.op.threshold {climdex.pcic} | R Documentation

## Number of days (less than, greater than, etc) a threshold

### Description

Produces sums of values that exceed (or are below) the specified threshold.

### Usage

    number.days.op.threshold(temp, date.factor, threshold, op = "<")

### Arguments

`temp` | Sequence temperature values.
`date.factor` | Factor to aggregate by.
`threshold` | Threshold to use.
`op` | Operator to use for comparison.

### Details

This function takes a data series, a threshold, an operator, and a factor to aggregate by. It uses the operator to compare the threshold to the data series, creating a series of booleans, then sums the booleans according to the factor.

### Value

A vector consisting of the number of values that meet the criteria in the given time period (as specified by `date.factor`).

### Examples

    library(PCICt)

    ## Parse the dates into PCICt.
    tmax.dates <- as.PCICt(do.call(paste, ec.1018935.tmax[,c("year",
    "jday")]), format="%Y %j", cal="gregorian")
    tmin.dates <- as.PCICt(do.call(paste, ec.1018935.tmin[,c("year",
    "jday")]), format="%Y %j", cal="gregorian")
    prec.dates <- as.PCICt(do.call(paste, ec.1018935.prec[,c("year",
    "jday")]), format="%Y %j", cal="gregorian")

    ## Load the data in.
    ci <- climdexInput.raw(ec.1018935.tmax$MAX_TEMP,
    ec.1018935.tmin$MIN_TEMP, ec.1018935.prec$ONE_DAY_PRECIPITATION,
    tmax.dates, tmin.dates, prec.dates, base.range=c(1971, 2000))

    ## Calculate frost days.
    fd <- number.days.op.threshold(ci@data$tmin,
                                   ci@date.factors$annual, 0, "<")

[Package climdex.pcic version 1.1-11 Index]