[R] Setting the names of a data.frame

[Ivan Calandra]

There is also a "header" argument in readHTMLtable()
About the file itself, can't you just erase the introductory text? There 
is also a skip argument to read.table() that might help you.
It's fine if my solution works, but I think it's still safer/easier to 
import the file directly with the correct headers
Ivan



Le 11/2/2010 17:51, Santosh Srinivas a écrit :
> 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.
>>>
>>> ______________________________________________
>>> R-help at r-project.org mailing list
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>>> PLEASE do read the posting guide
>> http://www.R-project.org/posting-guide.html
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>>>

-- 
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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