interpPairs: interpolate between pairs of vectors in a list In Ecfun: Functions for Ecdat

Description

This does two things:

1. Computes a `.proportion` interpolation between `pairs` by passing each pair with `.proportion` to `interpChar`. `interpChar` does standard linear interpolation with numerics and interpolates based on the number of characters with non-numerics.

2. Discards rows of interpolants for which `.proportion` is outside `validProportion`. If `object` is a `list`, corresponding rows of other vectors of the same length are also discarded.

NOTE: There are currently discrepancies between the documentation and the code over defaults when one but not both elements of a pair are provided. The code returns an answer. If that's not acceptable, provide the other half of the pair. After some experience is gathered, the question of defaults will be revisited and the code or the documentation will change.

Usage

 ``` 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23``` ```interpPairs(object, ...) ## S3 method for class 'call' interpPairs(object, nFrames=1, iFrame=nFrames, endFrames=round(0.2*nFrames), envir = parent.frame(), pairs=c('1'='\\.0\$', '2'='\\.1\$', replace0='', replace1='.2', replace2='.3'), validProportion=0:1, message0=character(0), ...) ## S3 method for class 'function' interpPairs(object, nFrames=1, iFrame=nFrames, endFrames=round(0.2*nFrames), envir = parent.frame(), pairs=c('1'='\\.0\$', '2'='\\.1\$', replace0='', replace1='.2', replace2='.3'), validProportion=0:1, message0=character(0), ...) ## S3 method for class 'list' interpPairs(object, .proportion, envir=list(), pairs=c('1'='\\.0\$', '2'='\\.1\$', replace0='', replace1='.2', replace2='.3'), validProportion=0:1, message0=character(0), ...) ```

Arguments

 `object` A `call`, `function`, `list` or `data.frame` with names possibly matching `pairs[1:2]`. When names matching both of `pairs[1:2]`, they are converted to potentially common names using `sub(pairs[i], pairs[3], ...)`. When matches are found among the potentially common names, they are passed with `.proportion` to `interpChar` to compute an interpolation. The matches are removed and replaced with the interpolant, shortened by excluding any rows for which `.proportion` is outside `validProportion`. Elements with "common names" that do not have a match are replaced by elements with the common names that have been shortened by omitting rows with `.proportion` outside `validProportion`. Thus, if `x.0` is found without `x.1`, `x.0` is removed and replaced by `x`. `nFrames` number of distinct plots to create. `iFrame` integer giving the index of the single frame to create. Default = nFrames. An error is thrown if both `iFrame` and `.proportion` are not `NULL`. `endFrames` Number of frames to hold constant at the end. `.proportion` a numeric vector assumed to lie between 0 and 1 specifying how far to go from suffixes[1] to suffixes[2]. For example, if `x.0` and `x.1` are found and are numeric, `x` = ```x.0 + .proportion * (x.1 - x.0)```. Rows of `x` and any other element of `object` of the same length are dropped for any `.proportion` outside `validProportion`. An error is thrown if both `iFrame` and `.proportion` are not `NULL`. `envir` environment / list to use with codeobject, which can optionally provide other variables to compute what gets plotted; see the example below using this argument. `pairs` a character vector of two regular expressions to identify elements of `object` between which to interpolate and three replacements. (1) The first of the three replacements is used in `sub` to convert each `pairs[1:2]` name found to the desired name of the interpolate. Common names found are then passed with `.proportion` to `interpChar`, which does the actual interpolation. (2, 3) `interpPairs` also calls `checkNames(object, avoid = pairs[c(1, 3, 2, 5)])`. This confirms that `object` has `names`, and all such names are unique. If `object` does not have names or has some duplicate names, the `make.names` is called to fix that problem, and any new names that match `pairs[1:2]` are modified using `sub` to avoid creating a new match. If the modification still matches `pairs[1:2]`, it generates an error. `validProportion` Range of values of `.proportion` to retain, as noted with the discussion of the `object` argument. `message0` a character string passed to `interpChar` to improve the value of diagnostic messages `...` optional arguments for `sub`

Details

*** FUNCTION ***

First `interpPairs.function` looks for arguments `firstFrame`, `lastFrame`, and `Keep`. If any of these are found, they are stored locally and removed from the function. If `iFrame` is provided, it is used with with these arguments plus `nFrames` and `endFrames` to compute `.proportion`.

If `.proportion` is outside `validProportion`, `interpPairs` does nothing, returning `enquote(NULL)`.

If `any(.proportion)` is inside `validProportion`, `interpPairs.function` next uses `grep` to look for arguments with names matching `pairs[1:2]`. If any are found, they are passed with `.proportion` to `interpChar`. The result is stored in the modified `object` with the common name obtained from `sub(pairs[i], pairs[3], ...)`, `i` = 1, 2.

The result is then evaluated and then returned.

*** LIST ***

1. ALL.OUT: if(none(0<=.proportion<=1))return 'no.op' = list(fun='return', value=NULL)

2. FIND PAIRS: Find names matching `pairs[1:2]` using `grep`. For example, names like `x.0` match the default `pairs[1]`, and names like `x.1` match the default `pairs[1]`.

3. MATCH PAIRS: Use ```sub(pairs[i], pairs[3], ...)``` for i = 1:2, to translate each name matching `pairs[1:2]` into something else for matching. For example, he default `pairs` thus translates, e.g., `x.0` and `x.1` both into `x`. In the output, `x.0` and `x.1` are dropped, replaced by `x` = ```interpChar(x.0, x.1, .proportion, ...)```. Rows with `.proportion` outside `validProportion` are dropped in `x`. Drop similar rows of any numeric or character vector or `data.frame` with the same number of rows as `x` or `.proportion`.

4. Add component `.proportion` to `envir` to make it available to `eval` any `language` component of `object` in the next step.

5. Loop over all elements of `object` to create `outList`, evaluating any expressions and computing the desired interpolation using `interpChar`. Computing `xleft` in this way allows `xright` to be specified later as `quote(xleft + xinch(0.6))`, for example. This can be used with a call to `rasterImageAdj`.

6. Let `N` = the maximum number of rows of elements of `outList` created by interpolation in the previous step. If `.proportion` is longer, set `N` = `length(.proportion)`. Find all vectors and `data.frame`s in `outList` with `N` rows and delete any rows for which `.proportion` is outside `validProportion`.

7. Delete the raw pairs found in steps 1-3, retaining the element with the target name computed in steps 4 and 5 above. For other elements of `object` modified in the previous step, retain the shortened form. Otherwise, retain the original, unevaluated element.

Value

a `list` with elements containing the interpolation results.

Author(s)

Spencer Graves

`interpChar` for details on interpolation. `compareLengths` for how lengths are checked and messages composed and written. `enquote`
 ``` 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 231 232 233 234 235 236 237 238 239 240 241 242 243 244 245 246 247 248 249 250``` ```### ### ### 1. interpPairs.function ### ### ## ## 1.1. simple ## plot0 <- quote(plot(0)) plot0. <- interpPairs(plot0) # check all.equal(plot0, plot0.) ## ## 1.2. no op ## noop <- interpPairs(plot0, iFrame=-1) # check all.equal(noop, enquote(NULL)) ## ## 1.3. a more typical example ## example function for interpPairs tstPlot <- function(){ plot(1:2, 1:2, type='n') lines(firstFrame=1:3, lastFrame=4, x.1=seq(1, 2, .5), y.1=x, z.0=0, z.1=1, txt.1=c('CRAN is', 'good', '...'), col='red') } tstbo <- body(tstPlot) iPlot <- interpPairs(tstbo[[2]]) # check iP <- quote(plot(1:2, 1:2, type='n')) all.equal(iPlot, iP) iLines <- interpPairs(tstbo[[3]], nFrames=5, iFrame=2) # check: # .proportion = (iFrame-firstFrame)/(lastFrame-firstFrame) # = c(1/3, 0, -1/3) # if x.0 = 0 and y.0 = 0 by default: iL <- quote(linex(x=c(1/3, 0), y=c(1/9, 0), z=c(1/3, 0), tst=c('CR', ''))) ## ##**** This example seems to give the wrong answer ##**** 2014-06-03: Ignore for the moment ## #all.equal(iLines, iL) ## ## 1.4. Don't throw a cryptic error with NULL ## ip0 <- interpPairs(quote(text(labels.1=NULL))) ### ### ### 2. interpPairs.list ### ### ## ## 2.1. (x.0, y.0, x.1, y.1) -> (x,y) ## tstList <- list(x.0=1:5, y.0=5:9, y.1=9:5, x.1=9, ignore=letters, col=1:5) xy <- interpPairs(tstList, 0.1) # check xy. <- list(ignore=letters, col=1:5, x=1:5 + 0.1*(9-1:5), y=5:9 + 0.1*(9:5-5:9) ) # New columns, 'x' and 'y', come after # columns 'col' and 'ignore' already in tstList all.equal(xy, xy.) ## ## 2.2. Select the middle 2: ## x=(1-(0,1))*3:4+0:1*0=(3,0) ## xy0 <- interpPairs(tstList[-4], c(-Inf, -1, 0, 1, 2) ) # check xy0. <- list(ignore=letters, col=3:4, x=c(3,0), y=7:6) all.equal(xy0, xy0.) ## ## 2.3. Null interpolation because of absence of y.1 and x.0 ## xy02 <- interpPairs(tstList[c(2, 4)], 0.1) # check #### NOT the current default answer; revisit later. xy02. <- list(y=5:9, x=9) # NOTE: length(x) = 1 = length(x.1) in testList #all.equal(xy02, xy02.) ## ## 2.4. Select an empty list (make sure this works) ## x0 <- interpPairs(list(), 0:1) # check x0. <- list() names(x0.) <- character(0) all.equal(x0, x0.) ## ## 2.5. subset one vector only ## xyz <- interpPairs(list(x=1:4), c(-1, 0, 1, 2)) # check xyz. <- list(x=2:3) all.equal(xyz, xyz.) ## ## 2.6. with elements of class call ## xc <- interpPairs(list(x=1:3, y=quote(x+sin(pi*x/6))), 0:1) # check xc. <- list(x=1:3, y=quote(x+sin(pi*x/6))) all.equal(xc, xc.) ## ## 2.7. text ## # 2 arguments j.5 <- interpPairs(list(x.0='', x.1=c('a', 'bc', 'def')), 0.5) # check j.5. <- list(x=c('a', 'bc', '')) all.equal(j.5, j.5.) ## ## 2.8. text, 1 argument as a list ## j.50 <- interpPairs(list(x.1=c('a', 'bc', 'def')), 0.5) # check all.equal(j.50, j.5.) ## ## 2.9. A more complicated example with elements to eval ## logo.jpg <- paste(R.home(), "doc", "html", "logo.jpg", sep = .Platform\$file.sep) if(require(jpeg)){ Rlogo <- readJPEG(logo.jpg) # argument list for a call to rasterImage or rasterImageAdj RlogoLoc <- list(image=Rlogo, xleft.0 = c(NZ=176.5,CH=172,US=171, CN=177,RU= 9.5,UK= 8), xleft.1 = c(NZ=176.5,CH= 9,US=-73.5,CN=125,RU= 37, UK= 2), ybottom.0=c(NZ=-37, CH=-34,US=-34, CN=-33,RU= 48, UK=47), ybottom.1=c(NZ=-37, CH= 47,US= 46, CN= 32,RU=55.6,UK=55), xright=quote(xleft+xinch(0.6)), ytop = quote(ybottom+yinch(0.6)), angle.0 =0, angle.1 =c(NZ=0,CH=3*360,US=5*360, CN=2*360,RU=360,UK=360) ) RlogoInterp <- interpPairs(RlogoLoc, .proportion=rep(c(0, -1), c(2, 4)) ) # check all.equal(names(RlogoInterp), c('image', 'xright', 'ytop', 'xleft', 'ybottom', 'angle')) # NOTE: 'xleft', and 'ybottom' were created in interpPairs, # and therefore come after 'xright' and 'ytop', which were # already there. ## ## 2.10. using envir ## RlogoDiag <- list(x0=quote(Rlogo.\$xleft), y0=quote(Rlogo.\$ybottom), x1=quote(Rlogo.\$xright), y1=quote(Rlogo.\$ytop) ) RlogoD <- interpPairs(RlogoDiag, .p=1, envir=list(Rlogo.=RlogoInterp) ) all.equal(RlogoD, RlogoDiag) } ## ## 2.11. assign; no interp but should work ## tstAsgn <- as.list(quote(op <- (1:3)^2)) intAsgn <- interpPairs(tstAsgn, 1) # check intA. <- tstAsgn names(intA.) <- c('X', 'X.3', 'X.2') all.equal(intAsgn, intA.) # op <- par(...) tstP <- quote(op <- par(mar=c(5, 4, 2, 2)+0.1)) tstPar <- as.list(tstP) intPar <- interpPairs(tstPar, 1) # check intP. <- list(quote(`<-`), quote(op), quote(par(mar=c(5, 4, 2, 2)+0.1)) ) names(intP.) <- c("X", 'X.3', 'X.2') all.equal(intPar, intP.) intP. <- interpPairs(tstP) all.equal(intP., tstP) ## ## NULL ## all.equal(interpPairs(NULL), quote(NULL)) ```