search for: drop_unused_levels

Hi all: I have an example that shows my problem: > test <- data.frame(c("a", "b", "c")) > colnames(test) <- "mm" > sub <- subset(test, mm=="b") > sub$mm [1] b Levels: a b c > levels(sub$mm) [1] "a" "b" "c" How can I reduce the levels to exclusively those which

I find that after subsetting (you may prefer "conditional selection") a data frame and assigning it to a new object, the str(new object) reflects the original data frame, not the new one: A <- rnorm(20) B <- factor(rep(c("t", "g"), 10)) C <- factor(rep(c("h", "l"), 10)) D <- data.frame(A, B, C) str(D) # reports correctly E <-

Hi! I'm doing: etni <- subset(etni, NAMECOM!="Maniquisito") where etni is a data.frame, NAMECOM a factor and "Maniquisito" labels a row that I want to delete. The problem is that while the row is deleted, the factor level is still there (I can see "Maniquisito" if I do levels(etni$NAMECOM) ). I know I can get the appropriate levels by:

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Hi! I have the following problem that I beleive is a bug: I have a dataframe with one categorical and one numerical vector. The categorical vector has three levels (uc, up and vc). A plot of the vectors with the categorical vector on the x-axis gives a boxplot with three boxes - exactly as expected. If I then use the subset function to make a dataset that only includes two of the levels of

Consider this data structure (df1) ... Group Year PctProf FullYr 1 Never RF 2004 87 88 2 Cohort 1 2004 83 84 3 Cohort 2 2004 84 86 4 Cohort 3 2004 87 87 5 Cohort 4 2004 73 74 6 Never RF 2005 85 86 7 Cohort 1 2005 81 82 8 Cohort 2 2005 81 81 9 Cohort 3 2005 78 79 10 Cohort 4 2005 72 74 11

Dear list, subset has a 'drop' argument that I had often mistaken for the one in [.factor which removes unused levels. Clearly it doesn't work that way, as shown below, d <- data.frame(x = factor(letters[1:15]), y = factor(LETTERS[1:3])) s <- subset(d, y=="A", drop=TRUE) str(s) 'data.frame': 5 obs. of 2 variables: $ x: Factor w/ 15 levels

Hi all, I am struggling to work out how to use the rownames from an edited dataframe rather than the row names from the original dataframe. In my data set i'm trying to extract several rows of data on particular individuals, i don't doubt i'm using the long way round but what i have in the way of a script is this: ##selecting the IDs from the dataframe individually

...rote: >  > ...  I get the four lines that I expected but the legend includes the > Group level "cohort 4" . >  > How can I get rid of "cohort 4" in Group? >  This link might be of interest for you: http://wiki.r-project.org/rwiki/doku.php?id=tips:data-manip:drop_unused_levels hth Stefan ------------------------------ Message: 108 Date: Wed, 27 May 2009 22:59:39 +0200 From: <mauede@alice.it> Subject: [R] R:  Harmonic Analysis To: "stephen sefick" <ssefick@gmail.com>, <r-help@stat.math.ethz.ch> Message-ID:     <6B32C438581E5D4C8A34C377C...