[R] colnames from read.table

Erik Iverson
Thu, 31 Jul 2008 02:56:38 -0000

Chua Siang Li wrote:
>    Hi.  May I know why the colnames is NULL when reading only 1 column from
a
>    csv file?

You are not "reading only 1 column from a csv file", you are
subsetting
one column of a data.frame.  See ?Extract and the "drop" argument
specifically.

How do I get the colname then?

?names in this case.  Always know the class of the object you are
dealing with, and which methods are defined for that class.

?class, ?methods


See
  Thanks.
>    > xy = read.table("dataFile.csv",header=T,
sep=",")
>    > y <- xy[,1]
>    > xDate <- xy[,2]
>    > x <- xy[,3:8]
>    > colnames(y)
>    NULL
>    > colnames(xDate)
>    NULL
>    > colnames(x)
>    [1]    "Market.Price"    "Quantity"
"Country"        "Incoterm"
>    "Channel"
>    [6] "PaymentTerm"
>    ----
>    Chua Siang Li
>    Consultant - Operations Research
>    Acceval Pte Ltd
>    Tel: 6297 8740
>    Email: siang.li.chua at acceval-intl.com
>    Website: www.acceval-intl.com
>    This message and any attachments (the
"message"...{{dropped:12}}
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