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Subtracting elements of data.frame
6 messages · Vincy Pyne, Dennis Murphy, Ivan Calandra +2 more
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Hi, Try this: df_new <- as.data.frame(lapply(df, FUN=function(x) x-x[1])) I hope it works! Ivan Le 1/25/2011 10:20, Vincy Pyne a ?crit :
Dear R helpers I have a dataframe as df = data.frame(x = c(1, 14, 3, 21, 11), y = c(102, 500, 40, 101, 189))
df
x y 1 1 102 2 14 500 3 3 40 4 21 101 5 11 189 # Actually I am having dataframe having multiple columns. I am just giving an example. I need to subtract all the rows of df by the first row of df i.e. I need to subtract each element of 'x' column by 1. Likewise I need to subtract all elements of column 'y' by 11. Thus I need an output like
df_new
x y 1 0 0 2 13 398 3 2 -62 4 20 -1 5 10 87 As I had mentioned above, I have number of columns in reality and thus I can't use the command say df_new = data.frame(x = df$x-df$x[1], y = df$y-df$y[1]) Kindly guide Thanking you all in advance Regards Vincy [[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.
Ivan CALANDRA PhD Student University of Hamburg Biozentrum Grindel und Zoologisches Museum Abt. S?ugetiere Martin-Luther-King-Platz 3 D-20146 Hamburg, GERMANY +49(0)40 42838 6231 ivan.calandra at uni-hamburg.de ********** http://www.for771.uni-bonn.de http://webapp5.rrz.uni-hamburg.de/mammals/eng/1525_8_1.php
I always forget about sapply(): df_new <- sapply(df, FUN=function(x) x-x[1]) Ivan Le 1/25/2011 10:33, Ivan Calandra a ?crit :
Hi, Try this: df_new <- as.data.frame(lapply(df, FUN=function(x) x-x[1])) I hope it works! Ivan Le 1/25/2011 10:20, Vincy Pyne a ?crit :
Dear R helpers I have a dataframe as df = data.frame(x = c(1, 14, 3, 21, 11), y = c(102, 500, 40, 101, 189))
df
x y 1 1 102 2 14 500 3 3 40 4 21 101 5 11 189 # Actually I am having dataframe having multiple columns. I am just giving an example. I need to subtract all the rows of df by the first row of df i.e. I need to subtract each element of 'x' column by 1. Likewise I need to subtract all elements of column 'y' by 11. Thus I need an output like
df_new
x y
1 0 0
2 13 398
3 2 -62
4 20 -1
5 10 87
As I had mentioned above, I have number of columns in reality and
thus I can't use the command
say
df_new = data.frame(x = df$x-df$x[1], y = df$y-df$y[1])
Kindly guide
Thanking you all in advance
Regards
Vincy
[[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.
Ivan CALANDRA PhD Student University of Hamburg Biozentrum Grindel und Zoologisches Museum Abt. S?ugetiere Martin-Luther-King-Platz 3 D-20146 Hamburg, GERMANY +49(0)40 42838 6231 ivan.calandra at uni-hamburg.de ********** http://www.for771.uni-bonn.de http://webapp5.rrz.uni-hamburg.de/mammals/eng/1525_8_1.php
On 2011-01-25 01:20, Vincy Pyne wrote:
Dear R helpers I have a dataframe as df = data.frame(x = c(1, 14, 3, 21, 11), y = c(102, 500, 40, 101, 189))
df
x y 1 1 102 2 14 500 3 3 40 4 21 101 5 11 189 # Actually I am having dataframe having multiple columns. I am just giving an example. I need to subtract all the rows of df by the first row of df i.e. I need to subtract each element of 'x' column by 1. Likewise I need to subtract all elements of column 'y' by 11. Thus I need an output like
df_new
x y 1 0 0 2 13 398 3 2 -62 4 20 -1 5 10 87 As I had mentioned above, I have number of columns in reality and thus I can't use the command say df_new = data.frame(x = df$x-df$x[1], y = df$y-df$y[1]) Kindly guide
You've already had good simple solutions. Here's one more,
using the plyr package:
require(plyr)
df_new <- colwise(.fun = function(x) {x - x[1]})(df)
plyr is very handy for all sorts of data manipulations.
Peter Ehlers
Thanking you all in advance Regards Vincy [[alternative HTML version deleted]]
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