R help - Jul 2009 - Multiplication of data frame with vector

Dear group:
sorry for my beginners question, but I'm rather new to R and was searching
high and low without success:

I have a data frame (df) with variables in the rows and observations in the
columns like (the actual data frame has 15 columns and 1789 rows):

          early1 early2 early3 early4 early5
M386T1000  57056  55372  58012  55546  57309
M336T90    11063  10312  10674  10840  11208
M427T91    12064  11956  12692  12340  11924
M429T91     4594   3890   4096   4019   4204
M447T90    26553  27647  26889  26751  26929

Now I'm trying to transform each value column-wise to make columns to all
have the same mean with:

df * mean(mean(df)) / mean(df).

I just can't get my head around this: mean(df) gives me the correct column
means vector, and mean(mean(df)) gives me the correct total mean. The above
operation works correctly for individual rows, i.e. if I do
 df[1,]*mean(mean(df))/mean(df)

Can someone tell me what I am doing wrong??
Thanks!

Hi

r-help-bounces at r-project.org napsal dne 07.07.2009 10:05:09:
> 
> Dear group:
> sorry for my beginners question, but I'm rather new to R and was 
searching 
> high and low without success:
> 
> I have a data frame (df) with variables in the rows and observations in 
the 
> columns like (the actual data frame has 15 columns and 1789 rows):
> 
>           early1 early2 early3 early4 early5
> M386T1000  57056  55372  58012  55546  57309
> M336T90    11063  10312  10674  10840  11208
> M427T91    12064  11956  12692  12340  11924
> M429T91     4594   3890   4096   4019   4204
> M447T90    26553  27647  26889  26751  26929
> 
> Now I'm trying to transform each value column-wise to make columns to 
all have
> the same mean with:
> 
> df * mean(mean(df)) / mean(df).
> 
> I just can't get my head around this: mean(df) gives me the correct 
column 
> means vector, and mean(mean(df)) gives me the correct total mean. The 
above 
> operation works correctly for individual rows, i.e. if I do
>  df[1,]*mean(mean(df))/mean(df)
a little bit awkward

t(t(as.matrix(df))*mean(mean(df))/mean(df))

or with apply
ttt<-mean(mean(df))/mean(df)
t(apply(df, 1, function(x) x*ttt))

There could be some sapply version of it but at present time I can not 
find it.
Regards
Petr
> 
> Can someone tell me what I am doing wrong??
> Thanks!
> 
> ______________________________________________
> 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.

Would the scale function work for this?  Something like
new=scale(df, center=T)

HTH,
david freedman

cir p wrote:
> 
> 
> Dear group:
> sorry for my beginners question, but I'm rather new to R and was
searching
> high and low without success:
> 
> I have a data frame (df) with variables in the rows and observations in
> the columns like (the actual data frame has 15 columns and 1789 rows):
> 
>           early1 early2 early3 early4 early5
> M386T1000  57056  55372  58012  55546  57309
> M336T90    11063  10312  10674  10840  11208
> M427T91    12064  11956  12692  12340  11924
> M429T91     4594   3890   4096   4019   4204
> M447T90    26553  27647  26889  26751  26929
> 
> Now I'm trying to transform each value column-wise to make columns to
all
> have the same mean with:
> 
> df * mean(mean(df)) / mean(df).
> 
> I just can't get my head around this: mean(df) gives me the correct
column
> means vector, and mean(mean(df)) gives me the correct total mean. The
> above operation works correctly for individual rows, i.e. if I do
>  df[1,]*mean(mean(df))/mean(df)
> 
> Can someone tell me what I am doing wrong??
> Thanks!
> 
> ______________________________________________
> 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.
> 
> 
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