documents:111012rtricks
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documents:111012rtricks [2013/09/24 10:28] – [Inserting math formula & symbols in label or title] kota | documents:111012rtricks [2016/05/24 12:46] – external edit 127.0.0.1 | ||
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+ | ====== R Tricks ====== | ||
+ | ===== removing trailing zeros from a vector ===== | ||
+ | |||
+ | When you import data from the out put of other software, you might have trailing 0s at the end of each column: | ||
+ | < | ||
+ | > d0 | ||
+ | [1] 69.444 70.889 86.667 95.667 83.444 78.333 67.889 | ||
+ | [8] 56.000 49.222 40.333 37.889 31.889 30.333 26.667 | ||
+ | [15] 22.444 23.111 20.889 22.000 20.111 19.778 20.778 | ||
+ | [22] 19.667 17.333 19.333 19.000 16.333 14.444 13.889 | ||
+ | [29] 18.000 21.778 23.556 23.889 28.778 40.000 48.667 | ||
+ | [36] 55.889 66.667 78.889 72.222 84.778 68.778 69.444 | ||
+ | [43] 0.000 0.000 0.000 0.000 0.000 0.000 0.000 | ||
+ | [50] 0.000 0.000 0.000 0.000 0.000 0.000 0.000 | ||
+ | [57] 0.000 0.000 0.000 0.000 0.000 0.000 0.000 | ||
+ | [64] 0.000 0.000 0.000 0.000 | ||
+ | </ | ||
+ | To remove them, there could be many ways, but here is my one liner. | ||
+ | <code R> | ||
+ | d0c <- d0[rev(cumsum(rev(d0)))> | ||
+ | </ | ||
+ | Then the output is | ||
+ | < | ||
+ | > d0c | ||
+ | [1] 69.444 70.889 86.667 95.667 83.444 78.333 67.889 | ||
+ | [8] 56.000 49.222 40.333 37.889 31.889 30.333 26.667 | ||
+ | [15] 22.444 23.111 20.889 22.000 20.111 19.778 20.778 | ||
+ | [22] 19.667 17.333 19.333 19.000 16.333 14.444 13.889 | ||
+ | [29] 18.000 21.778 23.556 23.889 28.778 40.000 48.667 | ||
+ | [36] 55.889 66.667 78.889 72.222 84.778 68.778 69.444 | ||
+ | </ | ||
+ | |||
+ | ===== Plotting a matrix data as a color-coded image ===== | ||
+ | |||
+ | <sxh> | ||
+ | #a 2Dplot, color coded. | ||
+ | x <- c(1:20) | ||
+ | y <- c(1:10) | ||
+ | for(j in y){ | ||
+ | for(i in x){ | ||
+ | val <- i+j | ||
+ | if((i == 0) & (j == 0)) z <- val | ||
+ | elsez <- append(z, val) | ||
+ | } | ||
+ | } | ||
+ | |||
+ | z <- matrix(z, nrow=20, ncol=10) | ||
+ | mat <- list(x, y, z) | ||
+ | image(x, y, z) | ||
+ | </ | ||
+ | |||
+ | [{{: | ||
+ | |||
+ | ... a bit faster way calculation wise uses indexing. | ||
+ | <sxh> | ||
+ | width <- 10 | ||
+ | height <- 20 | ||
+ | x <- c(1:width) | ||
+ | y <- c(1:height) | ||
+ | xindex <-rep(x, length = width*height) | ||
+ | yindex <- yindexing(x, | ||
+ | |||
+ | z <- xindex + yindex | ||
+ | |||
+ | z <- matrix(z, nrow=width, ncol=height) | ||
+ | mat <- list(x, y, z) | ||
+ | image(x, y, z) | ||
+ | |||
+ | yindexing <- function (x, y) { | ||
+ | for(i in y){ | ||
+ | cr <- rep(i, length=length(x)) | ||
+ | if (i==1) all <- cr | ||
+ | else all <- append(all, cr) | ||
+ | } | ||
+ | return (all) | ||
+ | } | ||
+ | </ | ||
+ | |||
+ | ===== Inserting math formula & symbols in label or title ===== | ||
+ | |||
+ | The easiest way is to use function // | ||
+ | < | ||
+ | plot(back$V2, | ||
+ | </ | ||
+ | Inserts vertically centered dot in the x label between " | ||
+ | < | ||
+ | ?plotmath | ||
+ | </ | ||
+ | |||
+ | More recent, but under development is using [[http:// | ||
+ | |||
+ | ===== Variable Name to String ===== | ||
+ | |||
+ | < | ||
+ | myfunc <- function(v1) { | ||
+ | deparse(substitute(v1)) | ||
+ | } | ||
+ | |||
+ | myfunc(foo) | ||
+ | [1] " | ||
+ | </ |
documents/111012rtricks.txt · Last modified: 2020/11/26 07:08 by kota