[R] Basic structure operations doubt
jwiley.psych at gmail.com
Mon Oct 18 04:16:31 CEST 2010
The easiest way to get rid of the empty levels is with droplevels().
See ?droplevels for details. It actually has a method for data frames
even. So you could just do something like:
Indx_Constituents <- droplevels(Indx_Constituents)
or whatever your data frame was called and it will drop any unused
levels for you.
On Sun, Oct 17, 2010 at 7:06 PM, Santosh Srinivas
<santosh.srinivas at gmail.com> wrote:
> I'm doing these manipulations on the data frame and wondering why does R
> have to remember historical data on my operation and not just keep the
> needed info.
> Probably a basic fundamentals of the way R handles data .. Pls point me to
> the manual if possible ..
> I have this Index data:
> Constituents.list.of.S.P.CNX.Nifty X X.1
> X.2 X.3
> 2 Company Name Industry Symbol
> Series ISIN Code
> 4 ACC Ltd. CEMENT AND CEMENT PRODUCTS ACC
> EQ INE012A01025
> 5 Ambuja Cements Ltd. CEMENT AND CEMENT PRODUCTS AMBUJACEM
> EQ INE079A01024
> 6 Axis Bank Ltd. BANKS AXISBANK
> EQ INE238A01026
> I Import the section that is relevant to me:
>> Indx_Constituents <- NIFTY_INDX[4:NROW(NIFTY_INDX),]
> Constituents.list.of.S.P.CNX.Nifty X
> X.1 X.2 X.3
> 4 ACC Ltd. CEMENT AND CEMENT PRODUCTS
> ACC EQ INE012A01025
> 5 Ambuja Cements Ltd. CEMENT AND CEMENT PRODUCTS
> AMBUJACEM EQ INE079A01024
> 6 Axis Bank Ltd. BANKS
> AXISBANK EQ INE238A01026
> 7 Bajaj Auto Ltd. AUTOMOBILES - 2 AND 3 WHEELERS
> BAJAJ-AUTO EQ INE917I01010
> 8 Bharat Heavy Electricals Ltd. ELECTRICAL EQUIPMENT
> BHEL EQ INE257A01018
> 9 Bharat Petroleum Corporation Ltd. REFINERIES
> BPCL EQ INE029A01011
>> colNames <- NIFTY_INDX[2,]
> Constituents.list.of.S.P.CNX.Nifty X X.1 X.2 X.3
> 2 Company Name Industry Symbol Series ISIN Code
> I want to assign the info from colNames[1,] to Indx_Constituents .... I am
> unable to do this directly ... I can probably pull out the values and do it
> but there should be an easier way
> Now when I do this:
>  Company Name
> 52 Levels: ACC Ltd. Ambuja Cements Ltd. Axis Bank Ltd. Bajaj Auto Ltd.
> Bharat Heavy Electricals Ltd. Bharat Petroleum Corporation Ltd. Bharti
> Airtel Ltd. Cairn India Ltd. Cipla Ltd. Company Name ... Wipro Ltd.
> Why does R have to remember the 52 levels?? Why can't it just have the
> relevant data stored
> What are the alternatives so that I can simply have my needed data in my
> data frames?
> Thanks for your explanation.
> Thanks R-Helpers. Yes, this is a silly question and it will not be repeated!
> R-help at r-project.org mailing list
> PLEASE do read the posting guide http://www.R-project.org/posting-guide.html
> and provide commented, minimal, self-contained, reproducible code.
Ph.D. Student, Health Psychology
University of California, Los Angeles
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