R replaced values show up in table()

Question

Is there a way for replaced values not to show up in the table() function?

Problem is easily reproduceable under R-Studio Version 0.98.1062, R version 3.1.1

x <- c(1, 2, 3, 4, 5, 6, 7, 8, 9, 10)
y <- c("condition1", "condition2", "condition3", "condition1", "condition2", "condition3", "condition1", "condition2", "condition3", "condition1")
df <- data.frame(x, y)

Let's say I replace the name of "condition3" to "condition2"

df$y <- replace(df$y, df$y=="condition3","condition2")
table(df$y)

ouput =

condition1 condition2 condition3

4....................6......................0

Why does it print Condition3 in the table, when it has 0 values? I would like a function that replaces condition3, so that it is not there, not just in the dataframe, but also in any further analysis. Is there a better way to replace values?

See also a more general Q&A: http://stackoverflow.com/questions/1195826/dropping-factor-levels-in-a-subsetted-data-frame-in-r — Henrik, Sep 27 '14 at 11:43

score 2 · Answer 1 · answered Sep 27 '14 at 11:29

2

You can use droplevels, like this:

table(droplevels(df$y))
# 
# condition1 condition2 
#          4          6

answered Sep 27 '14 at 11:29

A5C1D2H2I1M1N2O1R2T1

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@user2673238 If this answer is perfect for you, it's considered good pratice to accept the answer. See also this help page: [What should I do when someone answers my question?](http://stackoverflow.com/help/someone-answers) – Jaap Sep 28 '14 at 11:32

score 0 · Answer 2 · answered Sep 28 '14 at 03:27

0

Also,to permanently remove "condition3" from the levels of df$y,

df$y <- factor(df$y)

answered Sep 28 '14 at 03:27

branch.lizard

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R replaced values show up in table()

2 Answers2