Using do.call factor to scale - resetting value error

问题

This is an extension of the question that I asked here: Getting Factor Means into the dataset after calculation

Now that I have basically normalized all of the stats that I am interested in using I want to search the data set for people that intersect with these. Thus I am searching the dataset like this:

base3[((base3$ScaledAVG>2)&(base3$ScaledOBP>2)&(base3$ScaledK.AB<.20)),]

looking for the players that have all three of those things true, yet when I run this it resets the Scaled K.AB value to either .5, 1 or 2 and then doesn't search using that parameter. Is there something wrong with searching the data set this way or is there a better way to find people in a dataset in this same vein?

Here is some sample data but it doesn't have the same problems as when I go out to the 4000 records I have:

AVG = c(.350,.400,.320,.220,.100,.250,.400,.450)
Conf = c("SEC","ACC","SEC","B12","P12","ACC","B12","P12")
OBP = c(.360,.420,.360,.260,.160,.260,.460,.410)
K.AB = c(.11,.10,.09,.25,.20,.19,.05,.09)
Conf=as.factor(Conf)
d<- data.frame(Conf, AVG,OBP,K.AB)
dd <- do.call(rbind, by(d, d$Conf, FUN=function(x) { x$Scaled <- scale(x$AVG); x}))
dd <- do.call(rbind, by(d, d$Conf, FUN=function(x) { x$Scaled <- scale(x$OBP); x}))
dd <- do.call(rbind, by(d, d$Conf, FUN=function(x) { x$Scaled <- scale(x$K.AB); x}))
dd[((dd$ScaledAVG>2)&(dd$ScaledOBP>2)&(dd$ScaledK.AB<.20)),]

Thank you!

回答1:

You may want to drop the do.call(rbind, by(...)) strategy in favor of a straight scale strategy. The scale function has adata.frame` method.

> dd <- scale(d[ ,c("AVG", "OBP", "K.AB")])
> dd
             AVG        OBP       K.AB
[1,]  0.33566727  0.2348519 -0.3608439
[2,]  0.76878633  0.8281619 -0.5051815
[3,]  0.07579584  0.2348519 -0.6495191
[4,] -0.79044229 -0.7539981  1.6598820
[5,] -1.82992803 -1.7428481  0.9381942
[6,] -0.53057085 -0.7539981  0.7938566
[7,]  0.76878633  1.2237019 -1.2268693
[8,]  1.20190539  0.7292769 -0.6495191
attr(,"scaled:center")
    AVG     OBP    K.AB 
0.31125 0.33625 0.13500 
attr(,"scaled:scale")
       AVG        OBP       K.AB 
0.11544170 0.10112757 0.06928203 

> d[ dd[, 'AVG'] > 2 & dd[ ,'OBP'] >2 & dd[ ,'K.AB'] < 0.2 , ]
[1] Conf AVG  OBP  K.AB
<0 rows> (or 0-length row.names)

It should not be too surprising that you get no rows that meet all of those conditions since a scaled value of 2 is rather unlikely in a small dataset.

To apply scale within levels of Conf:

> dd <- lapply(d[ ,c("AVG", "OBP", "K.AB")], function(x) ave(x, d[,"Conf"] , FUN=scale) )
> dd
$AVG
[1]  0.7071068  0.7071068 -0.7071068 -0.7071068 -0.7071068 -0.7071068  0.7071068  0.7071068

$OBP
[1]        NaN  0.7071068        NaN -0.7071068 -0.7071068 -0.7071068  0.7071068  0.7071068

$K.AB
[1]  0.7071068 -0.7071068 -0.7071068  0.7071068  0.7071068  0.7071068 -0.7071068 -0.7071068

> data.frame(dd)
         AVG        OBP       K.AB
1  0.7071068        NaN  0.7071068
2  0.7071068  0.7071068 -0.7071068
3 -0.7071068        NaN -0.7071068
4 -0.7071068 -0.7071068  0.7071068
5 -0.7071068 -0.7071068  0.7071068
6 -0.7071068 -0.7071068  0.7071068
7  0.7071068  0.7071068 -0.7071068
8  0.7071068  0.7071068 -0.7071068

I do not think it works too well here because the offered test case is too small.

来源：https://stackoverflow.com/questions/15593537/using-do-call-factor-to-scale-resetting-value-error

标签

normalization

r-factor

do.call