[R] Setting the names of a data.frame

[Santosh Srinivas]

It is just read from a file that has introductory text in the beginning and
a the header starts slight below .... so couldn’t use header as such.
I just modified that dataset to ignore the earlier lines ... sHeaders =
tData[4,] &  tData = tData [5:end]

The original data was actually a readHTMLtable from a webpage.

Your solutions works well enough for my purpose ... thanks.


-----Original Message-----
From: Ivan Calandra [mailto:ivan.calandra at uni-hamburg.de] 
Sent: 02 November 2010 22:15
To: Santosh Srinivas
Cc: r-help at r-project.org
Subject: Re: [R] Setting the names of a data.frame

Wait wait,

If sHeaders is actually the first line of tData, the question is how do 
you create/read this dataset in R? Isn't read from a text/csv file? In 
that case, set the "header" argument to TRUE. If not, there are probably 
better ways to do it, better than what you did (i.e. extract the first 
line and reuse it).

In any case, that would be easier then (though still not the best way):
names(tData) <- unlist(lapply(tData[1, ], FUN=as.character))

Ivan

Le 11/2/2010 16:09, Santosh Srinivas a écrit :
> Thanks.
>
> Actually the sHeaders was a line in tData itself ...
> I just did sHeaders = tData [1,]
>
> How can I can build it without factors like your first suggestions?
>
> -----Original Message-----
> From: r-help-bounces at r-project.org [mailto:r-help-bounces at r-project.org]
On
> Behalf Of Ivan Calandra
> Sent: 02 November 2010 20:22
> To: r-help at r-project.org
> Subject: Re: [R] Setting the names of a data.frame
>
> Hi,
>
> The problem is that all your columns of sHeaders are factors. It might
> be better to set stringsAsFactors to FALSE when you build it.
>
> Or you can do it with a for loop like this:
> for (i in 1:length(sHeaders)){
>    names(tData)[i]<- as.character(sHeaders[1,i])
> }
>
> Or with lapply:
> names(tData)<- unlist(lapply(sHeaders[1, ], FUN=as.character))
>
> HTH,
> Ivan
>
> Le 11/2/2010 14:58, Santosh Srinivas a écrit :
>> I have tData as below. I need to set the names with the headers from the
>> first row in sHeaders
>> Sorry .. forgot how to set the names from row in another data frame ..
pls
>> advise.
>>
>> names(tData) = sHeaders[1,] does not work correctly
>>
>> Also, why doesn't drop.levels(sHeaders) not work?
>>
>> dput(tData)
>> structure(list(V1 = structure(c(3L, 1L, 1L, 2L), .Label = c("P H Ravi
>> Kumar",
>> "Rahul Kumar Singh", "Ramu GSV"), class = "factor"), V2 = structure(c(1L,
>> 3L, 3L, 2L), .Label = c("05/10/2010", "09/09/2010", "30/09/2010"
>> ), class = "factor"), V3 = structure(c(2L, 1L, 1L, 2L), .Label = c("B",
>> "S"), class = "factor"), V4 = structure(c(2L, 3L, 3L, 1L), .Label =
>> c("2120",
>> "4000", "11000"), class = "factor"), V5 = structure(c(1L, 2L,
>> 2L, 1L), .Label = c("", "0.01"), class = "factor"), V6 = structure(c(2L,
>> 3L, 3L, 1L), .Label = c("765", "1000", "11000"), class = "factor"),
>>       V7 = structure(c(1L, 2L, 2L, 1L), .Label = c("", "0.01"), class =
>> "factor")), .Names = c("V1",
>> "V2", "V3", "V4", "V5", "V6", "V7"), row.names = 5:8, class =
> "data.frame")
>>
>> dput(sHeaders)
>> structure(list(V1 = structure(1L, .Label = c("Name of Acquirer / Seller",
>> "Qty", "Ramu GSV"), class = "factor"), V2 = structure(3L, .Label =
>> c("05/10/2010",
>> "%", "Transaction Date"), class = "factor"), V3 = structure(1L, .Label =
>> c("Buy /Sale",
>> "Qty", "S"), class = "factor"), V4 = structure(3L, .Label = c("4000",
>> "%", "No.of Shares Transacted"), class = "factor"), V5 = structure(2L,
>> .Label = c("",
>> "Holding after Transaction"), class = "factor"), V6 =
> structure(NA_integer_,
>> .Label = "1000", class = "factor"),
>>       V7 = structure(NA_integer_, .Label = "", class = "factor")), .Names
=
>> c("V1",
>> "V2", "V3", "V4", "V5", "V6", "V7"), row.names = 3L, class =
"data.frame")
>>
>>
>> Thanks very  much.
>>
>> ______________________________________________
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>> PLEASE do read the posting guide
> http://www.R-project.org/posting-guide.html
>> and provide commented, minimal, self-contained, reproducible code.
>>

-- 
Ivan CALANDRA
PhD Student
University of Hamburg
Biozentrum Grindel und Zoologisches Museum
Abt. Säugetiere
Martin-Luther-King-Platz 3
D-20146 Hamburg, GERMANY
+49(0)40 42838 6231
ivan.calandra at uni-hamburg.de

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