# [R] Z score

arun smartpink111 at yahoo.com
Wed Oct 24 12:53:30 CEST 2012

```Hi,

In cases, with more sample columns, you could also use this:
res2<-t(sapply(lapply(apply(MyFile,1,function(x) x[!is.na(x)]),function(x) (x-mean(x))/sd(x)),function(x) x[colnames(MyFile)] ))
res2
#        Sample_1   Sample_2   Sample_3
#Gene_1  0.4931970 -1.1507929  0.6575959
#Gene_2  1.1421818 -0.7179429 -0.4242390
#Gene_3 -0.5773503  1.1547005 -0.5773503
#Gene_4 -0.7071068         NA  0.7071068
A.K.

----- Original Message -----
From: Vedant Sharma <vedantgeet at gmail.com>
To: R help <r-help at r-project.org>
Cc:
Sent: Wednesday, October 24, 2012 2:17 AM
Subject: [R] Z score

Hi,

I need to find the z-score of the data present in a speardsheet. The values
needs to be calculated for each gene across the samples (refer the
example). And, it should be a simple thing, but I am unable to do it right
now !

The example re the structure of the spreadsheet is  -

# Example:

"Names,'Sample_1','Sample_2','Sample_3'
Gene_1,87,77,88
Gene_2,98,22,34
Gene_3,33,43,33
Gene_4,78,,81
", header=TRUE, row.names=1, as.is=TRUE, quote="'", na.strings="" )

And, I think this formula that can be used for z score is -

(x-mean(x))/sd(x)

And, apply() function for rows should work. But bottomline - I am unable to
do it correctly.

Could you show me - using apply () or some other alternative function.

Thank you.

Cheers,
Ved

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