The eval() function evaluates an expression, but “5+5″ is a string, not an expression. Use parse() with text=<string> to change the string into an expression: > eval(parse(text=”5+5”)) [1] 10 > class(“5+5”) [1] “character” > class(parse(text=”5+5″)) [1] “expression” Calling eval() invokes many behaviours, some are not immediately obvious: > class(eval(parse(text=”5+5″))) [1] “numeric” > class(eval(parse(text=”gray”))) [1] “function” … Read more
If you don’t want to modify the list in-place (e.g. for passing the list with an element removed to a function), you can use indexing: negative indices mean “don’t include this element”. x <- list(“a”, “b”, “c”, “d”, “e”); # example list x[-2]; # without 2nd element x[-c(2, 3)]; # without 2nd and 3rd Also, … Read more
Using reshape function: reshape(dat1, idvar = “name”, timevar = “numbers”, direction = “wide”)
For a small number of variables, you can build the plot manually yourself: ggplot(test_data, aes(date)) + geom_line(aes(y = var0, colour = “var0”)) + geom_line(aes(y = var1, colour = “var1”))
@GavinSimpson: reorder is a powerful and effective solution for this: ggplot(theTable, aes(x=reorder(Position,Position, function(x)-length(x)))) + geom_bar()
Use the grepl function grepl( needle, haystack, fixed = TRUE) like so: grepl(value, chars, fixed = TRUE) # TRUE Use ?grepl to find out more.
Your dataframe has four columns like so df[,c(1,2,3,4)]. Note the first comma means keep all the rows, and the 1,2,3,4 refers to the columns. To change the order as in the above question do df2[,c(1,3,2,4)] If you want to output this file as a csv, do write.csv(df2, file=”somedf.csv”)
As of R 3.2.0 a new function was introduced for removing leading/trailing white spaces: trimws() See: Remove Leading/Trailing Whitespace
First make some data: > df = data.frame(matrix(rnorm(20), nrow=10)) > df X1 X2 1 0.7091409 -1.4061361 2 -1.1334614 -0.1973846 3 2.3343391 -0.4385071 4 -0.9040278 -0.6593677 5 0.4180331 -1.2592415 6 0.7572246 -0.5463655 7 -0.8996483 0.4231117 8 -1.0356774 -0.1640883 9 -0.3983045 0.7157506 10 -0.9060305 2.3234110 Then select some rows at random: > df[sample(nrow(df), 3), ] X1 X2 … Read more
Any ggplots side-by-side (or n plots on a grid) The function grid.arrange() in the gridExtra package will combine multiple plots; this is how you put two side by side. require(gridExtra) plot1 <- qplot(1) plot2 <- qplot(1) grid.arrange(plot1, plot2, ncol=2) This is useful when the two plots are not based on the same data, for example … Read more