[R] Subtracting elements of data.frame

[Ivan Calandra]

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 écrit :
> 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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>> and provide commented, minimal, self-contained, reproducible code.
>

-- 
Ivan CALANDRA
PhD Student
University of Hamburg
Biozentrum Grindel und Zoologisches Museum
Abt. Säugetiere
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+49(0)40 42838 6231
ivan.calandra at uni-hamburg.de

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