pkg/R/utils.R

   1 #' dateIndexToInteger
   2 #'
   3 #' Transform a (potential) date index into an integer (relative to data)
   4 #'
   5 #' @param index Date (or integer) index
   6 #' @param data Object of class \code{Data}
   7 #'
   8 #' @export
   9 dateIndexToInteger = function(index, data)
  10 {
  11     #works on integers too: trust input
  12     if (is.numeric(index))
  13         index = as.integer(index)
  14     if (is.integer(index))
  15         return (index)
  16
  17     if (inherits(index, "Date") || is.character(index))
  18     {
  19         tryCatch(indexAsDate <- as.Date(index), error=function(e) stop("Unrecognized index format"))
  20         #TODO: tz arg to difftime ?
  21         integerIndex <- round( as.numeric(
  22             difftime(indexAsDate, as.Date(data$getTime(1)[1])) ) ) + 1
  23         if (integerIndex >= 1 && integerIndex <= data$getSize())
  24             return (integerIndex)
  25         stop("Date outside data range")
  26     }
  27     stop("Unrecognized index format")
  28 }
  29
  30 #' integerIndexToDate
  31 #'
  32 #' Transform an integer index to date index (relative to data)
  33 #'
  34 #' @param index Date (or integer) index
  35 #' @param data Object of class \code{Data}
  36 #'
  37 #' @export
  38 integerIndexToDate = function(index, data)
  39 {
  40     #works on dates too: trust input
  41     if (is.character(index))
  42         index = as.Date(index)
  43     if (is(index,"Date"))
  44         return (index)
  45
  46     index = index[1]
  47     if (is.numeric(index))
  48         index = as.integer(index)
  49     if (!is.integer(index))
  50         stop("'index' should be a date or integer")
  51     as.Date( data$getTime(index)[1] )
  52 }
  53
  54 #' getSimilarDaysIndices
  55 #'
  56 #' Find similar days indices in the past.
  57 #'
  58 #' @param index Day index (numeric or date)
  59 #' @param limit Maximum number of indices to return
  60 #' @param same_season Should the indices correspond to day in same season?
  61 #'
  62 #' @export
  63 getSimilarDaysIndices = function(index, limit, same_season)
  64 {
  65     index = dateIndexToInteger(index)
  66
  67     #TODO: mardi similaire à lundi mercredi jeudi aussi ...etc
  68     if (!same_season)
  69     {
  70         #take all similar days in recent past
  71         nb_days = min( (index-1) %/% 7, limit)
  72         return ( rep(index,nb_days) - 7*seq_len(nb_days) )
  73     }
  74
  75     #Look for similar days in similar season (+/- 30 days)
  76     days = c()
  77     i = index
  78     while (i >= 1 && length(days) < limit)
  79     {
  80         if (i < index)
  81         {
  82             days = c(days, i)
  83             #look in the "future of the past"
  84             for (j in 1:4)
  85                 days = c(days, i+7*j)
  86         }
  87         #...and in the "past of the past"
  88         for (j in 1:4)
  89         {
  90             if (i - 7*j >= 1)
  91                 days = c(days, i-7*j)
  92         }
  93         # TODO: exact computation instead of -364
  94         # 364 = closest multiple of 7 to 365 - drift along the years... but not so many years so OK
  95         i = i - 364
  96     }
  97
  98     return ( days[1:min(limit,length(days))] )
  99 }
 100
 101 #' getNoNA2
 102 #'
 103 #' Get indices in data of no-NA series followed by no-NA, within [first,last] range.
 104 #'
 105 #' @param data Object of class Data
 106 #' @param first First index (included)
 107 #' @param last Last index (included)
 108 #'
 109 #' @export
 110 getNoNA2 = function(data, first, last)
 111 {
 112     (first:last)[ sapply(first:last, function(i)
 113         !any( is.na(data$getCenteredSerie(i)) | is.na(data$getCenteredSerie(i+1)) )
 114     ) ]
 115 }