How do you order a nominale variable. e.g month in R?

Question

This is a very basic problem but I do not find an answer. How can I order my variable "Month" so that when I make a bar plot January is first, then February...?

Thank you so much,

can you give a reproducible example ( http://tinyurl.com/reproducible-000 ) please ? — Ben Bolker, Apr 05 '13 at 03:10

score 5 · Accepted Answer · answered Apr 05 '13 at 03:09

5

@PhilipPham's answer is correct: this is equivalent but a little simpler:

Month <- factor(Month,levels=month.name)

since there is a built-in month.name variable in R that gives the English month names in order.

answered Apr 05 '13 at 03:09

Ben Bolker

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score 2 · Answer 2 · answered Apr 04 '13 at 21:44

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df$Month <- factor(df$Month,format(seq(as.Date("2013-01-01"),by="1 month",length=12),"%B"))

Then, plot again.

answered Apr 04 '13 at 21:44

ppham27

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Thank you! In fact my column already contains only the month : "January", "February"... but I a wondering what to write in the barplot script to get January before February... because right now it is in alphabetical order... – siva974 Apr 04 '13 at 21:49

score 2 · Answer 3 · answered Nov 16 '15 at 08:09

2

Adding to the answer from Ben (since I cannot add comments yet), you can do the following, assuming you have a dataframe with a Month column:

df$Month <- factor(df$Month,levels=month.name)
df = df[order(df$Month,decreasing=FALSE),]

answered Nov 16 '15 at 08:09

Joben R. Ilagan

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How do you order a nominale variable. e.g month in R?

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