documents:111012rtricks
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documents:111012rtricks [2012/02/14 22:21] – kota | documents:111012rtricks [2012/07/11 15:10] – 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) | ||
- | } | ||
- | </ |
documents/111012rtricks.txt · Last modified: 2020/11/26 07:08 by kota