[R] newbie help: simple operations in R

Tue Jun 2 15:03:34 CEST 2009

thats true actually,

The new variables will be one character too long to fit back into quattro, 
but you can make a new data frame or just use one of the more elegant 
solutions provided by Petr.

Cheers.

----- Original Message ----- 
From: "Petr PIKAL" <petr.pikal at precheza.cz>
To: "Carletto Rossi" <nuovodna at gmail.com>
Cc: <r-help at r-project.org>
Sent: Tuesday, June 02, 2009 1:22 PM
Subject: Re: [R] newbie help: simple operations in R

> Hi
>
> Carletto Rossi <nuovodna at gmail.com> napsal dne 02.06.2009 14:12:12:
>
>> I'm sorry but i verify that Simon solution doesn't work. It makes only
> the
>
> It partially works
>
>> product between the corrispondent element of the columns (first with
> first,
>> second with seconds, etc,...)
>> These are the list of R commands:
>>
>> > quattro <- read.csv('new_data.csv', header=TRUE)
>> > names(quattro)<-c("x","y")
>> > x<-c(NA,quattro$x)
>> > y<-c(quattro$y,NA)
>> > quattro$t<-quattro$x*quattro$y
>
> x and y is not quattro$x and quattro$y try
>
> quattro$t<-x*y
>
> instead although itself it does not work too. It throws error as x*y has
> one value more then is length of your quattro data frame. You need to drop
> either first or last value from x*y, it depends on you.
>
> e.g.
> quattro$t<-(x*y)[-1]
>
> Regards
> Petr
>
>
>
>> > write.table(quattro,file="with_t.csv",sep="")
>>
>>
>> This is the new_data.csv file
>>
>> "Y/h","u/U_b"
>> 0.16067E-02,-0.11652E-01
>> 0.48616E-02,-0.28583E-01
>> 0.82005E-02,-0.40079E-01
>> 0.11625E-01,-0.47481E-01
>> 0.15139E-01,-0.52047E-01
>> 0.18743E-01,-0.54658E-01
>> 0.22439E-01,-0.55902E-01
>> 0.26231E-01,-0.56181E-01
>> 0.30121E-01,-0.55777E-01
>> 0.34111E-01,-0.54897E-01
>> 0.38204E-01,-0.53696E-01
>> 0.42403E-01,-0.52267E-01
>> 0.46709E-01,-0.50663E-01
>> 0.51126E-01,-0.48919E-01
>> 0.55658E-01,-0.47059E-01
>> 0.60306E-01,-0.45100E-01
>> 0.65073E-01,-0.43057E-01
>> 0.69964E-01,-0.40940E-01
>> 0.74980E-01,-0.38733E-01
>> 0.80126E-01,-0.36428E-01
>> 0.85404E-01,-0.34044E-01
>> 0.90817E-01,-0.31620E-01
>> 0.96371E-01,-0.29153E-01
>> 0.10207E+00,-0.26602E-01
>> 0.10791E+00,-0.23957E-01
>> 0.11390E+00,-0.21238E-01
>>
>> This is the with_t.csv new file:
>>
>> "x","y","t"
>> "1",0.0016067,-0.011652,-1.87212684e-05
>> "2",0.0048616,-0.028583,-0.0001389591128
>> "3",0.0082005,-0.040079,-0.0003286678395
>> "4",0.011625,-0.047481,-0.000551966625
>> "5",0.015139,-0.052047,-0.000787939533
>> "6",0.018743,-0.054658,-0.001024454894
>> "7",0.022439,-0.055902,-0.001254384978
>> "8",0.026231,-0.056181,-0.001473683811
>> "9",0.030121,-0.055777,-0.001680059017
>> "10",0.034111,-0.054897,-0.001872591567
>> "11",0.038204,-0.053696,-0.002051401984
>> "12",0.042403,-0.052267,-0.002216277601
>> "13",0.046709,-0.050663,-0.002366418067
>> "14",0.051126,-0.048919,-0.002501032794
>> "15",0.055658,-0.047059,-0.002619209822
>> "16",0.060306,-0.0451,-0.0027198006
>> "17",0.065073,-0.043057,-0.002801848161
>> "18",0.069964,-0.04094,-0.00286432616
>> "19",0.07498,-0.038733,-0.00290420034
>> "20",0.080126,-0.036428,-0.002918829928
>> "21",0.085404,-0.034044,-0.002907493776
>> "22",0.090817,-0.03162,-0.00287163354
>> "23",0.096371,-0.029153,-0.002809503763
>> "24",0.10207,-0.026602,-0.00271526614
>> "25",0.10791,-0.023957,-0.00258519987
>> "26",0.1139,-0.021238,-0.0024190082
>>
>> Thanks.
>> Regards
>>
>> PS Can i avoid to print the column with "1","2","3","4", etc... ??
>>
>>
>>
>
>> 2009/6/2 Petr PIKAL <petr.pikal at precheza.cz>
>> Hi
>>
>> r-help-bounces at r-project.org napsal dne 02.06.2009 13:20:26:
>>
>> > The solution I provided should work
>> >
>> > First off all give your data frame shorter and easier names e.g.
>> >
>> > names(quatrro)<-c("x","y",etc)
>> >
>> > since you want y(n)*x(n+1) an easy way to code this is to add on an
> "NA"
>> to
>> > the start of x so everything shifts down a row and add an NA on the
> end
>> of Y
>> > so that X and Y are the same length. look up the concatentae function
> ?c
>> to
>> > understand this.
>> >
>> > Data frame is not a problem. In that case its...
>> >
>> > x<-c(NA,quattro$x)
>> > y<-c(quattro$y,NA)
>> > quattro$t<-quattro$x*quatrro$y
>
>> Above will not work as your result has one value more then original data
>> frame
>>
>> > df$t<-c(df$x,NA)*c(NA,df$y)
>> Error in `$<-.data.frame`(`*tmp*`, "t", value = c(NA, 3, 28, NA)) :
>>  replacement has 4 rows, data has 3
>> >
>>
>> She need to drop the appropriate one.
>>
>> Regards
>> Petr
>>
>> >
>> > then
>> >
>> > write.table(quattro,file="where you want the table to go.csv",sep="")
>> >
>> > HTH, Si.
>> >
>> >
>> >
>> >   ----- Original Message -----
>> >   From: Carletto Rossi
>> >   To: Simon Pickett ; r-help at r-project.org
>> >   Sent: Tuesday, June 02, 2009 12:03 PM
>> >   Subject: Re: [R] newbie help: simple operations in R
>> >
>> >
>> >   I' ve tried your suggestions but the results are wrong.I don't
>> > understand...i explain my request in a new way.
>> >   I have this table named data-4-bk.csv
>> >
>> >   "Y/h","u/U_b","v/U_b","uu/U_b^2","vv/U_b^2","uv/U_b^2","k/U_b^2"
>> >
>>
> 0.16067E-02,-0.11652E-01,0.30712E-04,0.11377E-02,0.37886E-06,-0.12657E-05,0.13570E-02
>> >
>>
> 0.48616E-02,-0.28583E-01,-0.10085E-03,0.72322E-02,0.44299E-04,-0.17874E-04,0.78991E-02
>> >
>>
> 0.82005E-02,-0.40079E-01,-0.25124E-03,0.14272E-01,0.23333E-03,-0.75078E-04,0.15054E-01
>> >
>>
> 0.11625E-01,-0.47481E-01,-0.50081E-03,0.19783E-01,0.60134E-03,-0.17623E-03,0.20764E-01
>> >
>>
> 0.15139E-01,-0.52047E-01,-0.78504E-03,0.23607E-01,0.11297E-02,-0.31123E-03,0.25042E-01
>> >
>>
> 0.18743E-01,-0.54658E-01,-0.11273E-02,0.26189E-01,0.17884E-02,-0.46941E-03,0.28287E-01
>> >
>>
> 0.22439E-01,-0.55902E-01,-0.15016E-02,0.27935E-01,0.25450E-02,-0.64447E-03,0.30825E-01
>> >
>>
> 0.26231E-01,-0.56181E-01,-0.19149E-02,0.29136E-01,0.33728E-02,-0.83204E-03,0.32881E-01
>> >
>>
> 0.30121E-01,-0.55777E-01,-0.23570E-02,0.29974E-01,0.42480E-02,-0.10299E-02,0.34591E-01
>> >
>>
> 0.34111E-01,-0.54897E-01,-0.28303E-02,0.30577E-01,0.51528E-02,-0.12376E-02,0.36045E-01
>> >
>>
> 0.38204E-01,-0.53696E-01,-0.33293E-02,0.31034E-01,0.60717E-02,-0.14533E-02,0.37305E-01
>> >
>>
> 0.42403E-01,-0.52267E-01,-0.38533E-02,0.31403E-01,0.69931E-02,-0.16763E-02,0.38415E-01
>> >
>>
> 0.46709E-01,-0.50663E-01,-0.43996E-02,0.31712E-01,0.79083E-02,-0.19064E-02,0.39403E-01
>> >
>> >   I give these R commands to import the file
>> >
>> >   quattro <- read.csv('data-4-bk.csv', header=TRUE)
>> >   attach(quattro)
>> >   names(quattro)
>> >
>> >   Then i'd like to calculate the new variable "t" defined as:
>> >
>> >   First element of u/U_b column * Second element of Y/h column
>> >   Second element of u/U_b column * Third element of Y/h column
>> >   etc.. etc..
>> >
>> >   Now i' d like to print the values of t as a new column on the
> original
>> data-4-bk.csv
>> >
>> >   Thanks and sorry for my newbie request.
>> >
>> >
>> >
>> >
>> >
>> >
>> >   2009/6/2 Simon Pickett <simon.pickett at bto.org>
>> >
>> >     you could use a loop but maybe easier would be
>> >     x<-c(NA,x)
>> >     y<-c(y,NA)
>> >     t<-x*y
>> >
>> >     use write.table() to write the table to your hard drive
>> >
>> >     e.g.
>> >
>> >     write.table(t, file="C:/Documents and Settings/simonp/My
>> Documents/RELU/
>> > GIS data/Land Cover Map working/squares plus adjoining
> parcels/Scotland/
>> > scotland adj squares.csv", sep = ",",row.names = F)
>> >
>> >     HTH, Si.
>> >
>> >     ----- Original Message ----- From: "Carletto Rossi"
>> <nuovodna at gmail.com>
>> >     To: <r-help at r-project.org>
>> >     Sent: Tuesday, June 02, 2009 11:22 AM
>> >     Subject: [R] newbie help: simple operations in R
>> >
>> >
>> >
>> >       Hi, i' d like to use R for simple calculations. I show you an
>> examples to
>> >       make clear my help request
>> >
>> >       I' ve a file .csv like this (my real file is composed by 10.000
>> lines and 8
>> >       columns)
>> >
>> >       x y
>> >       3 4
>> >       1 7
>> >
>> >       I' ve imported in R correctly. Now i want create a new variable
>> named "t"
>> >       and t is defined throught this relation:
>> >
>> >       t = 4 (second element on x column) * 4 (first element on y
> column)
>> >
>> >       in what way can i calculate t and print its value on an external
>> file or,
>> >       better, append t values as a column on my original csv???
>> >
>> >       Thanks
>> >
>> >       Emanuele
>> >
>> >
>> >       [[alternative HTML version deleted]]
>> >
>> >       ______________________________________________
>> >       R-help at r-project.org mailing list
>> >       https://stat.ethz.ch/mailman/listinfo/r-help
>> >       PLEASE do read the posting guide
>> http://www.R-project.org/posting-guide.html
>> >       and provide commented, minimal, self-contained, reproducible
> code.
>> >
>> >
>> >
>> >
>> >
>> >
>> >    [[alternative HTML version deleted]]
>> >
>> > ______________________________________________
>> > R-help at r-project.org mailing list
>> > https://stat.ethz.ch/mailman/listinfo/r-help
>> > PLEASE do read the posting guide
>> http://www.R-project.org/posting-guide.html
>> > and provide commented, minimal, self-contained, reproducible code.
>
> ______________________________________________
> R-help at r-project.org mailing list
> https://stat.ethz.ch/mailman/listinfo/r-help
> PLEASE do read the posting guide 
> http://www.R-project.org/posting-guide.html
> and provide commented, minimal, self-contained, reproducible code.
>