[R] Subtracting elements of data.frame

[Ivan Calandra]

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 écrit :
> 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]]
>
>
>
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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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