24 lines
1006 B
R
24 lines
1006 B
R
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# Goal: To read in a simple data file where date data is present.
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# Suppose you have a file "x.data" which looks like this:
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# 1997-07-04,3.1,4
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# 1997-07-05,7.2,19
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# 1997-07-07,1.7,2
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# 1997-07-08,1.1,13
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A <- read.table("x.data", sep=",",
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col.names=c("date", "my1", "my2"))
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A$date <- as.Date(A$date, format="%Y-%m-%d")
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# Say ?strptime to learn how to use "%" to specify
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# other date formats. Two examples --
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# "15/12/2002" needs "%d/%m/%Y"
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# "03 Jun 1997" needs "%d %b %Y"
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# Actually, if you're using the ISO 8601 date format, i.e.
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# "%Y-%m-%d", that's the default setting and you don't need to
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# specify the format.
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A$newcol <- A$my1 + A$my2 # Makes a new column in A
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newvar <- A$my1 - A$my2 # Makes a new R object "newvar"
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A$my1 <- NULL # Delete the `my1' column
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summary(A) # Makes summary statistics
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